Only recently I found out about Mark Probst's MathMap plugin for the GIMP. I ran into it when he posted about a new feature in it called the MathMap Composer.
Check out this video demostration of MathMap's Composer.
I would have put a good screen capture of it, but Google Video seems to have regressed and no longer lets user skip over parts of the video.
Posted on 04 Feb 2008