MacDevCenter.com: Hacking Radio on the Mac
Features a couple of low-cost audio editing apps, the Griffin RadioShark and the Griffin RoadTrip.
The comments list some notable ommisions: Audio Hijack (record from any source, including the computer), RadioTime.com (TiVo for Radio) and Audacity (open source audio capture, editing and encoding)
More are sure to come.. Ahh the power of the blog..