There's a few apps out there in the iphone world for OBD Vehicle diagnostics... Check out Rev, seems to be the best one and most feature rich with a very nice GUI. DevToaster - Rev - iPhone app development, Great iPhone apps, and more Here's the issue with the current iphone apps for OBD diagnostics, THEY DON'T HAVE BLUETOOTH COMMUNICATION as an option for connecting to the car's com interface. You are forced to buy a $200 wifi adapter to plug into your car, ridiculous! I have a bluetooth OBD plug plugged in my truck right now, $29 .. works FANTASTIC with windows and on my mac.. I use ScanXL, works perfect, mounts as a COM port, I am not certain, but it seems that android 2.1+ supports COM through bluetooth right?... I know if there was an OBD diagnostics application for android with support through bluetooth communication that could show all sensor values and OBD2 engine codes, it would be sure to sell very well... Especially if the interface works with cheap bluetooth com interfaces unlike Rev on the iPhone.