The freeware stuff (I assume Audacity?) for some reason will not capture from the sound card on a Mac. Not sure why, but it doesn't. Audio HiJack will, and that's a good way to capture iTunes radio. The Windows version of Audacity will, and is quite effective. I've built quite a library using this method; you just need to make sure you aren't doing anything else on your Windows computer that will make it into the recording. (Fair Use; I don't share what I've captured.) Stream rippers can be detected and banned from the stream but Audio HiJack cannot.
While recording I note in a text file the artist, title, and album of what is being recorded (or more accurately, I wrote a script which goes and grabs it for me from their website while I'm recording the stream) for later tagging. You can use Audacity to extract the individual tracks and save them off to individual mp3s or AACs later.
Neither Audacity recording on Windows nor Audio HiJack recording on a Mac can be detected by the streaming station, but you have to do the work to tag each file later. I consider it a hobby of sorts. 128kbps streams are of sufficient quality for my ears, and burn CDs which are quite acceptable to listen to in the car. The encoded mp3s are also acceptible on the iPod.
To those who will decry this as 'stealing', this is no different from what we did back when recording broadcast radio onto 8-track tapes back in the '70s.