I have seen a lot of people looking for some "cheap" OBD-II interface hardware and associated software. I have also seen people asking if their car IS OBD-II compliant. Some 1993/4 models are, a LOT of 1995 are, and all 1996 and newer are OBD-II compliant.
On to the interface hardware and software:
They make a rather "inexpensive" (Cheap could be a bad word) OBD-II interface for Serial ports (USB only users, have no fear, a USB to serial converter works just fine). It costs $88.00 at the time of this writing.
The software is free, updates frequently and is downloadable (Its small too). It can read codes on almost every make/model car (Ford,chevy,doge,Honda/acura, isuzu, audi, bmw, mercedes, VW, saab, mazda, toyota/lexus, the list goes on and on) give you real time engine information (RPM, throttle position, engine load, fuel "offset" data, O2 sensor data, etc). In addition, it will give you plain english explainations of any codes on your car's engine computer, as well as allow you to see the "freeze frame" information recorded at the moment the code was set. You can also clear the codes, resetting the "check engine" light.
For those of you out there who want to record what your engine is doing over time, it allows you to record/log the session, then play it back at a later time (limited to hard drive space).
No, I don't work for the guy that makes it. I just got in a jam one time with my own car, and this little piece of hardware saved me over $300.00 (even if you count the purchase of the unit).
Clarion 9375 HU, 2X CDC1255 12 Disc changer, 7500 DSP/EQ/Xover (w/fiber optic interconnects), 7501 TV Tuner/Aux
Xtant 1001d 1 Ch, 4180c 4 ch
7" Xenarc VGA touchscreen
1GHz Via-Nehemiah, 250 GB HDD
XMPCR w/TOSLink, SB Audigy NX