Most of the channels are EDGE-friendly, so there is no need for a WiFi connection. To sign up for the service, all you need to do is point Safari on your iPhone or iPod Touch to flytunes.fm, and then follow the on-screen instructions to sign up.
How well does it work? Pretty darned good! It took me a minute to figure out that I needed to tap on the play button twice - once to bring up a small arrow and another tap to bring up the QuickTime player and start the stream. It only took about 5 seconds for the stream to queue up and start playing, and I didn't hear a hiccup once during about 5 minutes of listening over an EDGE connection.
Head on over to flytunes.fm and get your fill of free tunes today!