There's much talk on the debian-legal mailinglist about the GNU FDL. I've read a few of those mails, and I think some parts might be important for us, but I'm getting headaches. And I know that when I read a few more I'll get bellyache. But maybe someone else is interrested enough in these things:
http://lists.debian.org/debian-legal/2003/debian-legal-200305/
Happy reading!
Kurt