OK, maybe not Filezilla (which I've used to store pictures from a Cognex Insight networked vision system, which uses standard TCP protocols such as ftp and telnet), but a couple examples:

1. Subversion (free book, and they seem to be keeping it updated)
2. TortoiseSVN
3. Python
4. Lua (free book)
5. Setting up gcc to work with Eclipse on Windows to cross compile and download to Philips LPC ARM-7 chips (thanks to one person who has put together very detailed PDFs on this -- I'm working through this now)
6. The Trac documentation is a little scattered, but the Windows install directions were pretty good - once I figured out I couldn't use Python 2.4

To be fair, bad documentation is the normal rule. Interesting, of my six example of stuff I've used, the majority aren't GPL.

Tony