I recently purchased the REV from DEVTOASTER for the iphone, they call it Kiwi WiFi.
Does work but not all metrics are supported such as fuel level, mpg's are out to lunch says I only get 22mpg at 65 m/hr?
You can graph and log WHP,TRQ,FuelComsuption,MAF,MAP,IM, BOOST and several other features.
I was dissapointed for the price and having to buy the app form itunes.
If I had my time back, I would have gotten a ScangaugeII, but the WiFi is up there on the pretty cool scale, and you can move it from car to car.
http://www.devtoaster.com/products/rev/