I went to Austin this weekend back to hang with Skaven and go see Max Graham spin at Sky Lounge, on our way to 6th Street we were listening to some kickin tunes in his car. I asked what it was, he said it was Proton Radio. I thought for a second before asking how he recorded it...
I guess I never thought of looking for an MP3 stream recorder, maybe I never wanted to record a stream bad enough. The whole idea was news to me. It's a simple concept, and they have existed for quite some time now. But for what it's worth, here is the MP3 Stream Recorder that I've been using lately.
This comes in especially handy if you have an MP3-compatible stereo in your car. ;)