iOBD2 reader from xtool (iobd2.co.uk).
This is pure plug and play. Download the free software from the Apple store to your iPhone, iPod, iPad (as many devices as you wish). Plug the reader in to the diagnostic port. Pair your device through WiFi (NOT Bluetooth!). Select your vehicle and "bingo" you now have full access.
Trouble codes can be read (in plain English as well as with Code value). Many other parameters are available through the configurable dashboards (giving real time read outs).
I have used this for some time (there are pics of the various dashboards on my build thread) and the only reason it is for sale is I have ditched my iPhone for a Galaxy and replaced this reader with the Android version.
Complete with box, instruction manual and price includes First Class postage.
For sale at £45
Manufacturers price is £62.
David