ALDL OBDII linking for sensor values

[PHXSYS at aol.com]

Hi

This is my first post. I have a project where I want to obtain sensor data 
directly to a microprocessor (PIC or Stamp). I want to get specific 
parameters: RPM, TPS,CTS,MAP/MAF, O2 maybe a few others and use that data to 
control some additional equipment I will add to the vehicle. I am adding and 
LPG system to my 1994 chevy p/u. With the flick of a switch I will be able to 
run on LPG or unleaded fuel. I thought this might be an easy way to get data 
through the diagnostic link to simplify the installation and wiring.

I am not really sure how to get started.

Here are some sites I have found that offer some info, but I need help seeing 
the big picture.

www.hit.net\~rah\disassnotes.html
www.isthq.com\~dan\aldl.htm
www.ag.auburn.edu\~gparmer\bookmark.htm
www.franken.de\users\dagobah\luke\scantool.html
http://www.obdii.com/obdii.html

Thanks

Jon