Kwkard, I have same query (refer Item #1 in this thread!).
Sure, if one wants to auto-disconnect WHEN a certain program/download finishes there are ways to do that.... but.... I like to go to sleep with streaming audio on, and have it disconnect after say 2 hours.
I use the 11k freeware "AutoDown " which is perfect, except it doesn't just disconnect from internet, but closes my whole PC.
I've also found a shareware program Auto-IP which DOES disconnect perfectly at predetermined time, but it seems overkill... 800k download, US$25, a zillion "other" features, etc etc..
Surely somewhere there's a simple tiny program to keep both me AND Kwkard happy !??