Happy weekend! Here's a girl from Korea, named applegirl002 over on YouTube, playing Lady Gaga's "Poker Face" with a quartet of iPhones as accompaniment. Sure, the song's not that great, but look at those iPhones go! She's using I am T-Pain for autotuning the singing, Beatmaker for laying out the beats, and ... she says "Analog" in the video. However, I think it's miniSynth that she's actually got running on the last iPhone.
You might not be gaga over Gaga (I'm definitely not), but running a whole choir of iPhones like that is quite impressive. It's also worth noting that she accomplished this feat without pulling in some of the more popular music apps like Bebot and Ocarina. It turns out that the iPhone is an excellent way to turn out some pretty complicated music.