Newegg has the ELM327 Bluetooth OBD2 Diagnostic Scan Tool for $12 with free shipping. Works with all OBD II compliant cars 1996 and newer, reads and clears diagnostic trouble codes, and can turn off the Check Engine light.
It it is like the one i got 1.5 years ago (looks the same) then it came with some software for a BT enabled PC's (maybe Linux/OSX but I'm not sure). I also got it to work with my wife's jailbroken iPad 2. If I find the apps ill add the info back here, but it required 2 apps (one from Cydia, the other was an AppStore one I believe) The Cydia app could connect to the adapter via BT then set up a http port for it. This was because the App was set to work with WiFi ODB adapters, at that point just enter the loopback (1201) and it worked like a champ. I would assume this would work on an iPhone too
Works great with the "Torque" App for Android: https://play.google.com/store/apps/details?id=org.prowl.torque
(There is also a free version to try: https://play.google.com/store/apps/details?id=org.prowl.torquefree)
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I've got one of these plus the full version of torque, and it's a pretty nice setup. Couldn't communicate with a 2004 Kia Optima, though.
It it is like the one i got 1.5 years ago (looks the same) then it came with some software for a BT enabled PC's (maybe Linux/OSX but I'm not sure). I also got it to work with my wife's jailbroken iPad 2. If I find the apps ill add the info back here, but it required 2 apps (one from Cydia, the other was an AppStore one I believe) The Cydia app could connect to the adapter via BT then set up a http port for it. This was because the App was set to work with WiFi ODB adapters, at that point just enter the loopback (1201) and it worked like a champ. I would assume this would work on an iPhone too
BT to HTTP (Cydia):
http://www.roqy-bluetooth.net/
WiFi ODB App (Apple AppStore)
http://itunes.apple.com/app/dashcommand-obd-ii-gauge-dashboards/id321293183?mt=8
Got 1 before and it works with LG Android phone. Used on 2001 Sonata, 2005 G6 and 2008 Saturn.