By CHARLES PASSY Cox News Service

WEST PALM BEACH -- The headline alone is enough to scare any parent: "Mother reports finding nude photos of teen daughter on MySpace.''

It happened last month in Martin County.

But it's one thing to be alarmed. It's another to take action. What advice do experts have for parents when it comes to dealing with the minefield of MySpace, Facebook and other social-networking sites?

Plenty, it turns out. Particularly since when we're talking about anything computer-related, it's often our sons and daughters who have the upper hand.

Says computer safety expert Kevin McDonald: "This whole social dynamic is being run by the children.''

An estimated 21 million teens - or 87 percent of those ages 12 to 17 - are online, according to the Pew Internet & American Life Project 2005 study. That same study also showed that 64 percent of teens and 66 percent of adults agree that their kids know more about the Internet than they do.

Most of these Web-savvy teens inevitably find their way to MySpace and/or its competitors.

While the risks can be overstated, social-networking sites do provide an entryway for child predators.

More common is the very real threat of cyber-bullying - teens taunting one another and crossing the line into truly dangerous (and illegal) behavior, whether posting compromising photos or threatening violence.

Even just goofing around, though, can have unintended consequences. Teens who post racy photos of themselves may not realize it, but they could be committing a crime. "In essence, it's transmission of child pornography,'' says Detective Cass Collins of the computer-crimes unit of the Palm Beach County Sheriff's Office.

Little wonder MySpace and more than 45 states worked out an agreement earlier this year to establish several safeguards, including those aimed at giving parents greater control over their children's ability to get on the site.

For parents, the first step, most experts agree, is to become Web-savvy -- perhaps even establish MySpace pages themselves.

"You're not going to parent your kids effectively in the 21st Century if you're uneducated about the role digital technology plays in their lives,'' writes Annie Fox, a San Francisco-based author and teacher who's an online adviser to teens.

The next step is to figure out how much freedom to allow your kids online.

Most experts advise parents of younger children to keep the computer in a common room, so activity can be closely monitored, and to establish some basic rules about avoiding contact with strangers.

By the time the child becomes a teen - technically, a child can't even establish a MySpace account (or "profile'') until they're 14 - the parameters can change. But even if a parent lets a teen have a computer in their own room, they can still stand guard.

In the case of MySpace, that means the parent can be a "friend'' on the child's account or have the password to the account, giving them the ability to see what's posted. As the child heads into the mid and late teens, the parent may elect to let go of the online tether, provided the child has proved responsible.

Either way, it doesn't hurt to let the child know online activities can come back to haunt them, especially in terms of applying to college or jobs.

"This information will follow the child for a long time,'' warns Dr. Debi Yohn, a psychologist who advises teens about applying for college.

But what if a parent insists on having access to a child's account and a child refuses? Or what if a parent suspects a child has a îîsecret'' account on MySpace or another social networking site, which they're not handling wisely? (It doesn't take much to establish a MySpace profile, which is why some child advocates have argued for better controls, such as needing a credit card to register with the site.)

The solution could be installing monitoring software - SpectorSoft is a popular brand - on a child's computer.

Which is not to say that anything is foolproof: A child can still access the Internet - and MySpace - from a cellphone or at a friend's house.

That's all the more reason to be aware of your options should a problem arise. MySpace gives parents the ability to report a concern or to shut down a child's account through its ParentCare program (www.myspace.com/index.cfm?fuseactionhelp.safetytips.parentcare).

Facebook doesn't offer as much - and its officials declined a request for an interview - but parents looking for a few basic tips can still find them on the site www.facebook.com/help.php?safety).

In spite of all this, it's important to realize the value of social-networking sites. Even the most concerned of child advocates will tell you they can be a useful tool for interaction, especially for shy teens.

And their significance has spread into the world of culture and commerce. Rock bands have their own MySpace pages. So do businesses.

Can your kid afford not to participate in the dialogue? "It's their intellectual and social development,'' says McDonald, board member of Web Wise Kids.

But also of concern: their safety. Proceed with caution.