Arwel,
Once I set up a user account for my lad, I was able to simply configure a report once a week that came to the email address I specified, as Jimmy says, its easy to delete internet activity, but the report isnt affected.
I dont have vista, but with XP, its easy to set controls based on language, age, and violence filters. You should also be able to set whether you want the user to be able to recieve instant messages, video chat etc.