Ok, Audi/VW dealers have a computer called VAS (I've often been told its name is "VAG", but i read VAS on it at my dealer). Once connected to your car, you can easily use it to reprogram the electrronics in the car. Now, What if I wanted to do the same wuth my laptop? DOes anybody know if there's some home made converter/adapter, and, of course, if there's any way to get the software or a compatible GPL version (I actually heard from a friend there could be one...)?

VAGcom... For GPL'ed stuff, look at OpenDiag

OpenDiag stalled a couple of years back. VAGcom is up to date and has a great reputation.

I have the VAG-COM that I bought from http://www.ross-tech.com . The UI is pretty bad (think bad shareware) but it works.

Here's a list of people willing to let you use their VAG-COM. (A 6 pack or something similar is the typical gesture of thanks.)

http://www.steve-hall.com/cgi-bin/VAG-Locator.pl

Find the appropriate forum for your car (probably at www.audiworld.com or www.vwvortex.com) for discussions on what can be done. Common things are:

change power lock behavior
window up/down from keyfob
allow fog lights to be used with high beams
put auto tranny in sport mode
clear check engine light (often evidence of engine mods)

On my Allroad you can change the air suspension ride hight for when you really want to pimp it out.