iOS6 and Bluetooth OBDII Adapters
Dash ( http://drivewithdash.com/ ) is promising a Bluetooth 4.0 ODB-II module, but it's not available yet; it's a Kickstarter project as of this writing ( http://www.kickstarter.com/projects/shred444/drive-with-dash ).

Also take a look at Automatic ( http://www.automatic.com/ ), as Brad Larson mentioned in the comments above.