The Internet is a wonderful resource for children. My 5-year-old son loves to look at the American Automobile Association's site for kids , play with trains at and watch the live kelp-forest camera at the Monterey Bay Aquarium . But that doesn't mean that we're going to turn him loose on the Internet--not now, and maybe not even 10 years from now. It's a sign of the times, but the world's just not that safe, and neither is the Internet.

What's dangerous about the Internet? Just as in the real world, there's sex, violence, deception and hatred. But unlike the real world, the sex, violence, deception and hatred can come right into your living room--or your kid's bedroom. If you're not paying attention, you may not know what's happening. But what's a caring parent to do?

The situation becomes more troubling because there are so many avenues into dangerous areas. Well-meaning children and adults alike can stumble across undesirable Web pages. Researching the Holocaust, for example, might as easily bring up a neo-Nazi site as genuine historical research. After the shootings at the Jewish Community Center in Los Angeles, it was nearly child's play to find hate-ridden sites created by white-supremacist organizations. An adult can tell the difference--but a child may not.

Even looking for a celebrity's fan club can cause problems. Web searches based on a feminine first name often return links to triple-X-rated graphics and pages--and obscenities are frequently included in the search engine's "description" of the site.

Search engines aren't the only entry point into rough waters. When a child "registers" for a Web site by providing a name, age or e-mail address--perhaps to enter a contest--that information could easily be sold to direct marketers, or worse. Unsavory lurkers could be in chat rooms or on one of the instant-messaging services.

All that assumes the best of intentions on behalf of the youngster. But not all children want to play in a sandbox; their natural instincts might make them want to sample forbidden wares. It's hard to nurture their need to explore, while keeping them safe. But it's possible.

The best place to start, particularly with young children, is to monitor their activities. Be there with them when they're using the Internet; guide them to sites that you know are safe. Your best judge of what's good is . . . you. Why not check out the sites in advance to see what's kid-friendly? You can find good advice from teachers, educational resources or family-oriented magazines.

If you have control over their Web-surfing computer, you're in a better position to protect them from at least accidental exposure to inappropriate material. The same may be true for computers in schools or libraries. You can protect kids by limiting the scope of the Internet experience in two ways: by blocking at the PC itself, or by ensuring that kids are using trusted sites and resources.

One place to start is at right at your Web browser. If you're using a recent version of Microsoft's Internet Explorer, for example, you can limit Web browsing to sites that have voluntarily rated their content. Select "Internet Options" from either the View or Tools menu, depending on which version you're using; click on the Content tab, and then Content Advisor. That lets you limit the viewing of sites based on adult language, nudity, sex and violence. If you click back to the General tab, you can set a password to control these settings and shut off access to sites that aren't rated. The problem is, most sites aren't rated, so this approach will wall off huge tracts of the Web.

Search engines are a problem area, because they can point children directly to dangerous Web sites. But some of these sites are working to fix this longstanding problem with features such as AltaVista's Family Filter, Lycos's SearchGuard and Yahoo's NetFind for Kids. These all prevent--in theory at least--objectionable material from being displayed after a Web search. Such features can't stop a mischievous kid from using a different search engine, but it's better than nothing.

A more useful and sophisticated approach is to install site-blocking software, which either limit access to sites on an "approved" list, block sites on a "forbidden" list or attempt to filter out sites by scanning their text. Perhaps the best known is Net Nanny Software International's NetNanny . This Windows-only software limits a child's access to inappropriate material via the Web, e-mail, chat rooms and other parts of the Internet. Two other products, available for both Windows and Macintosh, are SurfWatch Software's SurfWatch and the Learning Co.'s CyberPatrol . Both of these products, along with NetNanny, are effective, but not bulletproof, tools for keeping kids safe. Be aware that many people may object to having their Web experiences "censored," that all of these programs can screen out safe sites by mistake and that these programs can also be defeated by a sufficiently clever user.

The other thing is, you can't assume that the computer at home is your kid's only access to the Web. The Internet's increasing ubiquity makes it easier to access than ever before, in libraries, at a friend's house, at a local cybercafe. In those situations, work with your children's teachers to educate them as to what they're likely to encounter online, why it's there and what they should do when they find such sites. Teach them never, never, never to give out any personal information without your prior approval--that goes for Web sites, chat rooms or e-mail correspondence (not to mention offline).

Want to learn more? A new resource on the Web, called GetNetWise , is designed to help parents educate themselves and their children about how to use the Internet safely. The site, backed by the likes of America Online, AT&T, Microsoft and MCI WorldCom, lists tools and tips for staying out of trouble and getting the most out of the Net.