Available now on the App Store!
More information at http://earsmack.com/
This is a preliminary simulator-based demo of chipPad for iPad. In reality it does not do the app justice since it's all multi-touchy and whatnot and is a complete joy to jam on.
Please excuse my mouse-based screw up - that doesn't happen when you're jamming with your fingers ;-)
From the app store description: chipPad is a multi-track sample and loop playback and performance application. It is made for the musician who creates loop-based music and is looking to experiment with on-the-fly arrangements or to glitch it up a notch. By adding your own pre-cut loops on up to 8 tracks you can perform using various "grid-based" controller techniques and develop new ones that are only capable on a multi-touch device. Sliding one or multiple fingers back and forth on various tracks or tapping rhythms like on a drum machine can yield some amazing results you can't hear elsewhere. chipPad comes with a few sample sessions to get you started. Simply select Help from the Gear menu to get started or load your own AIF or WAV audio files into the app using File Sharing via iTunes.