Time shifting radio (specifically NPR)

[Travis Roy]

I used to have a TV/FM card in my linux box and recorded shows that way 
but that machine is long gone now and I've been looking for a way to 
timeshift from one of the internet feeds.

I'm most interested in their weekend lineup (Car Talk, Wait Wait, etc).

Does anybody on the list do this currently? What software would you suggest.

The only requirement is that it be in MP3 or AAC format (for my iPod)