I've seen plenty of videos in the past of composers using the latest iPhone, Windows Mobile and Android music composition tools, but this one is the best. Steffest built a guitar out of two Android devices, two Windows Mobile devices and one iPod touch. He then managed to play a rendition of Cracklin Rosie, and put the whole thing on video.
According to Steffest, the piano and drum sequencers are written by him, and Pocket Stombox is used for the real time effects. The final piece of the puzzle is the guitar, provided by the iShred app, by Frontierdesign.
Steffest created this masterpiece to show off his mad skills at mobile cross development. He thought he would code the same app and move it across all three dev environments, but in the end had to rewrite it three times, in Java (Android), C# (Windows Mobile), and Objective-C (iPhone). He'll be presenting his creation at MobileCampBrussels, so I'm sure we'll be seeing more videos soon.
You can read more about the composition and creation of this mobile guitar at his blog. It's an impressive video, not just to see all of the mobile phones pieced together, but also how effortlessly he strums such a tiny screen.