Check out replay radio. Pretty much it's TIVO for radio. They have a catalog of several hundred programs, you schedule what you want to record, and your PC does the rest. Pretty cool.
Thanks, Tyler. Looks like you're right — the site is at http://www.replay-radio.com/ — it offers more flexibility in that the rights management is much looser: you can store internet radio audio for as long as you like. So the RIAA may lobby even harder to get this stopped!