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.