Move the computer to a lounge room or household public area. The trouble starts when it's in a bedroom, and they haven't got any parental control over what there watching.
Take a lot of interest into what there doing, My Space, Twitter, U-Tube, and most of the other sites young people frequent, can be suspect. Remember it's the internet, and you can be anyone you like.
As Boknoy recommends install a safe-guard program, if you feel it's needed, and really while it will cost you *****, it's a cheap price to pay to keep the kids safe. But nothing beats a bit of parental education.
