Instant Media 1.2 (7.52 MB)is a free software that delivers TV shows to your PC. It's totally totally ad-ware and spyware free. Their patent pending media caching technology enables you to view high-quality, full screen video on your desktop.
It does have some minimum requirements though: Windows X, Windows Media Player 10 and Broadband Internet Connection
They have a selection of several hundred channels including CNN, MTV, ABC, etc.