Since the advent of the Web, parents have worried about children visiting pornographic and violent Web sites. Then filters like NetNanny came along to block them. Now parents worry about instant messaging, e-mail, and peer-to-peer file sharing. Whether kids are looking for trouble or it's looking for them, the latest parental-control software can help monitor them online.

This year's packages are smarter, stronger, and simpler. While overblocking can be a problem, developers constantly tune their lists and filters. And since kids are often more computer-savvy than parents, developers have hardened security. Yet ease of use is still a prerequisite; many parents will set up complicated apps wrong or not at all.

America Online and MSN (not reviewed here) have improved their filters. AOL uses lists and heuristic technology to block offensive sites and lets parents set online time limits. MSN 8 lets you monitor all applications that connect to the Internet and control IM, e-mail, and file downloads.

There's no substitute for supervision, but the following software can help protect your children—when you're watching and when you're not.

Our favorite parental-control package, Cybersitter 2002, covers sex, drugs, hate, and violence out of the box. Fine-tuning protection in over 30 categories—from cults to hacking—is simple. Specifying blocked or allowed sites is straightforward, and unlisted sites are filtered for content. Unlike its competitors, Cybersitter offers free list updates. (Click here to read the full review.)

CyberPatrol 6 delivers a generous assortment of protection and easy customization features for both tech-savvy and tech-naive parents. Context-sensitive menu trees make navigation simple, and URL and Web page analysis attempts to protect kids from pages not on the program's block list. With unlimited user profiles, parents can customize Internet and PC access for all family members. CyberPatrol was one of the first filters to let users set up daily and weekly time quotas.

By default, CyberPatrol's filter is set to the most restrictive configuration, but parents can customize it with a selection of 13 categories from the CyberNot list and add their own URLs and keywords. Like Cybersitter 2002 with its timed suspend mode, CyberPatrol switches back to the default user after a set time, protecting little ones even if you forget.

The program-blocking feature scans your PC and presents a large, potentially confusing list of applications for you to allow or block. The list lets you block RegEdit and Msconfig, which kids can use to hack protection features.

Our favorite parental-control package, Cybersitter 2002, covers sex, drugs, hate, and violence out of the box. Fine-tuning protection in over 30 categories—from cults to hacking—is simple. Specifying blocked or allowed sites is straightforward, and unlisted sites are filtered for content. Unlike its competitors, Cybersitter offers free list updates.

Running as a system tray icon or in stealth mode, Cybersitter blocks sites without fanfare; they simply don't appear. (Programs such as CyberPatrol require a log-on and spawn pop-ups at blocked sites.) The scheduler makes setting daily and weekly time limits easy, but you don't get separate user controls: Protection is either on or off. Parents can keep tabs on kids through daily logs, and parents with fixed IP addresses on their home systems can download a free utility from Solid Oak Software to monitor and configure Cybersitter remotely.

Cybersitter filters POP e-mail and instant messages by blanking out banned words; for Web-based e-mail it blocks entire messages with questionable content. The program can also block file sharing, IM, newsgroups, and FTP access.

Rather than blocking only inappropriate Web sites, Kidsnet blocks all sites except those included within the 125,000 TLDs (top-level domains) reviewed by the company's staff. Users must log on for Web access, and then Kidsnet checks each URL visited against an online database. It blocks sites that are not on the list, but it does not offer content filtering. This approach keeps kids safe but requires parents to make many judgment calls as kids try to access unrated sites.

Blocking level is determined by age, using ratings from the Internet Content Rating Association, though parents can customize settings. The database has 21 categories, and control within categories is granular, so parents can restrict graphic sex but allow artistic nudity, for example.

At each restricted site, the program explains that access is not approved and provides a link explaining how parents can manually override the decision. In our testing at the most restrictive level, Kids-net successfully blocked e-mail, IM, and newsgroups, as well as inappropriate sites.

McAfee Parental Controls 1.0 (MPC) is easy to set up and navigate, and it provides powerful protection for online kids. We like its tracking of visited sites, violations, and trigger categories or words. MPC is also available as part of McAfee Internet Security 5.0 ($79.99 direct), which includes antivirus, firewall, and privacy features.

With McAfee's Instant Updater parents can quickly get the latest blocked-site lists, then customize both block and allow lists for words and URLs. For unlisted sites, MPC detects inappropriate content via a word filter.

The program supports an unlimited number of users and, like CyberPatrol, can block applications so parents can protect QuickBooks records, for example. Parents can also specify personal information, such as phone numbers, that MPC will prevent kids from sending out.

MPC can filter Web, chat, or newsgroup access. Although it can filter Web-based e-mail and block inappropriate messages, it disappointingly doesn't filter POP e-mail, though you can disallow this type of mail. Newsgroups can be blocked, allowed, or restricted to a custom list.

Norton Parental Control is a no-frills, list-based filter available only with Norton Internet Security 2003, a suite that also includes antispam, antivirus, and firewall software. Without content filtering, though, parents must to more diligent than with Cybersitter 2002 or McAfee Parental Controls 1.0.

Parental Control lets parents identify users as child, teenager, or adult and further customize rules in 31 categories. It supports Windows XP fast user switching, automatically assigning limited user accounts the appropriate levels. You can also prevent personal information, such as credit card numbers, from leaking out via e-mail, newsgroup postings, or attachments.

The program's URL-based filters block only sites and newsgroups on Symantec's lists, which are customizable and updated via Norton Live Update. The Web history log shows user surfing activity, as well as violations with dates, user names, and links to the sites in question. Unfortunately, adding inappropriate logged sites to block lists isn't easy. And unlike Cybersitter and McAfee Parental Controls, which filter the content of unlisted sites, Norton Parental Control allows surfing of unlisted but inappropriate sites.

PAL Computer Surveillance System is for parents who want to monitor the apps their kids use, what they write, and where they go online. Its site blocking is rudimentary, though, banning only the sites you specify.

As with Cybersitter 2002, you can install PAL in a hidden mode. It records keystrokes and writes them to a date- and time-stamped text file. You can view the logs or have them e-mailed to you regularly or in response to alerts.

In our testing, word and phrase capture were inconsistent. For example, in Microsoft Outlook, PAL captured text in a choppy, difficult-to-follow format.

The keystroke recording logs only the local side of e-mail and instant messaging, but this lets parents discover screen names or passwords kids enter. PAL doesn't filter e-mail or IM; you either allow these or shut the clients down.

When kids enter banned URLs, PAL rudely shuts down the browser with no explanation or warning. PAL can also snap screenshots at regular intervals ranging from 6 seconds to 30 minutes.

Kid Defender, the first software release from hardware company Actiontec Electronics (http://www.actiontec.com/), offers parents something different: live monitoring. Kid Defender lets parents connect to children's machines and watch their surfing and messaging as it happens.

In the late beta version we tested, Kid Defender came with four licenses—for two parents and two children (additional child licenses are available). The kids' software does the filtering and reporting, while the parents' component does the remote monitoring. You can set preferences to block or allow sites, instant messaging, chat, and file downloads, as well as the music-sharing app Kazaa. You can also limit IM partners by screen name.

When a child goes online, Kid Defender can alert the parents via IM. It then logs every URL and chat room the child visits. Both sides of IM conversations are logged and relayed in real time. If a session turns ugly, the parent can remotely shut it down.

Kid Defender is a good solution for parents who want to watch over their child's shoulder but can't always be there in person.