A while ago I had the idea of using cheap bluetooth modules to operate an Arduino from a mobile phone, thus saving the expense of an IOIO board (or similar). I purchased the module, but it didn't arrive during a period of unemployment and I never got around to doing anything with it.
I'll have to give it a go one day. This will save me the trouble of doing it myself!
I wasn't sure whether a slave device would be fine, or whether I'd have to get the bluetooth module running in master mode. Someone has found out how to upload different firmware versions, to allow master mode in these devices.