I downloaded the full version of DashCommand and bought an OBDII Bluetooth Module, for a combined investment of ~ $16.
So, I use the smart phone to "Be" the OBD Reader, and it communicates directly via the blue tooth ports on the phone and OBD jack (The bluetooth module just plugs into the OBD port under the dash, the way a reader's jack would, etc)
I LEAVE the bluetooth jack on the OBD port, and I can look at my phone to read temps, rpm, codes, readiness of OBD sensors (I needed that to time inspections between engine light episodes...), clear codes, every thing my big 'ol regular OBD reader did, but with extra options, and, all in real time.
You can even recalibrate your ECU for larger tires, diff gear changes, etc...pretty cool stuff.