Try http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A788. It seems relatively current, and offers some GPL'd software and lots of links.

This is a bit outdated, possibly a dead project, but it was cool when it was new and going on. Check out http://members.shaw.ca/sonde/ [High Altitude Glider Project]. Might be enough interesting pieces there to continue a similar project, or at least contact the original site-owner and ask him a few questions to get you started.

Now I wonder (and I'm traveling down the "how do we defeat the GPL path, not a specific MySQL bashing) if this model of distribution is a potential flaw in the GPL? (bear with me whilst I work myself through this one).

Scenario: Let's say company X takes some super-cool GPL code, modifies that code, but only offers that modified code to customers paying for the binaries. Of course, in order to get the privilege of paying for the binaries, you have to sign a contract commercially stating you won't ask for the code, and/or you won't distribute that code. Thus, Company X can now charge for modified GPL code, without breaking the terms of the GPL for not distributing their modified code back to the community at large, since the only folks getting the binaries are people they have binding commercial contracts with...

I can't see the light at the end of the tunnel for this one. Seems ... dangerous.