They just announced a new one that works with a cell phone or... tablet? I actually read this before going to sleep last night and I'm not too clear on it, but it looks like some sort of UG/Torque hybrid.
Anyway I have the old kind, which plugs into the OBDII port and has a nice long wire, so you can mount it wherever you like. I put in a cell phone mount so I can take it back out when needed... it's handy to use it to diagnose problems with other cars and clear check engine lights.