I don't currently own any obd2 cars but the absolute coolest solution I've discovered recently is a bluetooth module like this one: Newegg.com - Super Mini ELM327 V1.5 OBDII OBD2 Interface Bluetooth Car Diagnostic Scanner
. There are a some others but I imagine they all use the same chip set and are just built by other companies. There is a smartphone app(android and iphone, I believe) called Torque that is about $5. If/when I get another car that is obd2, I would just leave this plugged in all the time. You could pull codes while eating your burger at the drive-in.