I bought Car Code's OBD-2 scanner http://www.obd-2.com and I was able to use it to clear the service light which was really bugging me. Just be careful if you buy it, you need a serial port that supports a speed of 10400 bps, which is a non-standard baud rate. If you have a notebook it probably does not come with an on-board serial port, and you will need a USB-RS232 converter. I recommend the ones that have FTDI chipset. Those work really well and support non-standard baud rates. Prolific PL-2303 based converters do not support 10400 bps. Too bad since they are very cheap and you can buy them anywhere.

The guy that writes the software apparently writes for the car companies. There is incredible support for GM, Chevrolet, Ford, Toyota, Subaru, etc.

Regarding Volvo, according to the software author, it supports communication to the different computers that are installed in the car (power seat, ABS, tranny, Engine, SRS, etc.) I was not able to get that working, but I could read the OBD-2 codes and I got P0000 (no DTCs), and the extended manufacturer DTCs which also returned P0000.

I have also requested confirmation regarding clearing the SRS malfunction indicator. I know there are several members that have triggered the SRS light when disassembling the dash or the airbag and have had to pay the dealer to clear the light.

I have emailed the author regarding problems communicating with the Volvo-specific modules, and I will post any updates here.