As a parent I am trying to make my son understand that being on the PC non stop is not healthy....so..... I installed Nanny Shutdown ... it works well but... there is always a but isn't it....he complains that now he can't do his homework using word, power point or else because Nanny Shutdown, shuts down the whole PC

Is there any way of controlling only the time spent on internet.

If I buy XBox live, then he will not sleep anymore.... same question.

Would some DLink router trick do the same?

Thank you for your suggestions, it is very appreciated.

   Back in the olden days when you paid for the internet by the minute or by the hour, there were internet timers.  I think they were for dial-up (yes, back in the olden days that was the only way to hook up to the internet), but maybe they would work for other types of internet connection too.  Surely, there would be some of these still around today.  You might try doing a search on download.com for internet timer or something like that.
   A better solution may be to only have internet connection on one computer in a public room, like the family room, and let him do his homework on another computer which has no way to be connected to the internet.  It is a bad idea for your child to have a computer in his room that has internet connection.  There is just too much that can go wrong with that.