Do you recall the Facebook privacy tool that let your updated status posts be seen on selected friend's walls?

[MeesterDork]

Creating friends list:
You first need to create a friends list for your children. You can do it in two ways the quick way and the not so quick way. :-) The quick way: click the chat button on the lower right corner of the window. At the top of that chat box or whatever you call that, you can see a Friend List button. Click it, name it, and add the people you would want included in it. I don't think you'd still want to know about the not-so-quick way, but ok, click "Account", "Edit Friends", "Create List". It's still easy, though.

Post filtering:
When posting a message on FB, you see a padlock right under the text area. It will allow you to choose which of your friends you want to be able to see that post.

You don't even need to create the friends list.; you can just type their names. But they come in handy.