bluetooth obd for android phones

[fellow dubber]

hi guys,
just bought myself an htc desire, good bit of kit. i have seen this app which lets you use it to find fault codes on your motor and displays all your cars values like rpm, speed, intake pressure, boost etc, just wondering if anyone here has used it?
is it any good and which bluetooth adapter did you get? theres so many on ebay i dont know where to start. i think if it works it would be a good little gadget to have.

any help would be great
cheers marty