You can buy a bluetooth OBD-II reader from numerous sources, including ebay. But I believe they don't work with iPhone, only PCs and Android phones. I heard something about Apple only supporting a limited number of bluetooth items, such as a keyboard or headset. The Android bluetooth interface is a little more "open". I use the torque app on my Android phone. It might be worth looking at an Android tablet...
So far, I've only been able to read the "public" OBD-II values, which means that the two EGT sensors I can read are post turbo. I'm not sure if there even is one pre-turbo; I think you have to buy a gauge and install the pyro by drilling the manifold to get a real EGT. Similarly, I don't think my manual transmission has a temperature sensor; I don't know if the automatic temp can be read thru the OBD-II or not.