I have done a fair amount of OBDII stuff. You are correct it is a pain that being said there is a really easy way to do it. I use ELM Electronics chips in my OBDII projects.

Homepage:
http://www.elmelectronics.com

Direct to chips:
http://www.elmelectronics.com/thehome.html#ELM320

They make individual chips for each type of vehicle or one "super" chip that can be used on any OBDII vehicle. The chip communicates with your PC (or PIC) via serial with ASCII commands. The interface, timing, and protocol to the vehicle is handled by the chip. Makes things really simple! For $14 you can’t really beat it.

Another good resource for software and example schematics using this chip:

www.scantool.net

Enjoy.