Does the Mazda 6 2005 have a connector I can use to get info from the on board sensors? If so is there a Bluetooth dongle/iPhone app for it. I am almost sure I have heard of such a thing but can't figure out what to google for to find it?
A 2005 car will be OBD-II so with an OBD-II dongle and some appropriate software you should be able to read the basic information you get via standard OBD-II. Depending on how Mazda implemented the connection you might well have to use Mazda-specific software to read all the information that the ECU can provide.