Streaming radio apps for the iPhone/iPod touch are exploding in 2009. TUAW favorite Pandora was updated to 2.0 a couple of weeks ago, but it's hardly the only game in town. Back at Macworld, Chris Pirillo showed me StarPlayr for the iPhone, which lets Sirius and XM Radio subscribers access stations via the iPhone. The app isn't available right now, but it'll hopefully be in the App Store soon.
Chris demoed the app extensively on his own site and having seen it in person, it is really impressive. Even with the crappy 3G signal we had on our trip to Cupertino, the stations streamed in at nice quality and there was an option to buy a track or album directly from iTunes. XM and Sirius both offer some great stations for talk radio and sports fans, and to me, that's where these types of streaming apps really shine.
Pandora and Last.fm aren't the only streaming radio services around, AOL's SHOUTcast Radio [iTunes link] app debuted in the App Store a few weeks ago and it'll stream your favorite SHOUTcast stations in up to 128k streams (go to Settings on your iPhone, select SHOUTcast and select "allow high-bit streams"), favorite radio stations, search for artists (though the currently-playing artists is a bit delayed) and peruse the extensive SHOUTcast index.