Stern Tech has open source software for an OBDII scanner. The software is for a hand held OBDII scanner which can also be connected to a PC. I would love it if someone would add the code such that it can support some of the PC software.
All the software is written in C thus it can be ported to PC fairly easy. The reason I did a hand held with PC connection over just a PC unit is that some times you do not want to drag around a PC just to check codes on a car. Thus having a handheld unit that does both seemed like the right answer.
The hardware can be purchased for $159 and the software is all available on Google's code site, which is linked from
www.sterntech.com
If you have any questions feel free to email me.
Trampas
obdii@sterntech.com