This may be of interest/useful (?):
http://en.wikipedia.org/wiki/Wikipedia:Software_screenshots
E.g. can images from Stellarium, a planetarium software under GPL v2, be used for public communication by an amateur astronomy association?
This is a really fun (fair-use and) copyright question! There are so many different edge cases with user data, fonts, creative use of the program, etc. that make it less simple than it might at first seem. I'd love to hear what others are thinking about this and if there have been any interesting law suits over screenshots or the like.
Josh