but I think you are looking for "Parental Control" settings and/or software, and that would be my first search item in Google.
Remote monitoring has been discussed before in these forums and frankly the discussion didn't get very far because of the implications. The discussion is here; http://forums.cnet.com/7723-6132_102-511893.html
But if you are asking about specific problems then we would need to know more, such as what computer, what OS? (Parental Control may be different for a Mac than it is for Windows, for example). What type of misuse, software downloading, P2P file downloading, virus and other malware infections?
Hope that helps.
I know there are many kinds of spy software and mobile spy just like the iphone spy, but I want to get the remote pc monitoring for free, as my son usually misuses the pc, could you help me pls?