Guillaume Bellec has been up to an interesting school project, using a couple of phones and TouchOSC to drum with!
Very cool! You can play with this project as well! All you need is PureData(free), and Guillaume's Gigote.pd patch. To download click the "File" menu at the top, and Download from the file menu. This is a really rough version, and not intended for release, but I asked him if we could play with it and he agreed!
For complete details his project thesis is available here.