Yesterday I checked out Lyx, a remarkable open source, freeware, text processing and formatting system based on the venerable LaTeX system with a GUI to make it palatable.
This is a remarkable piece of engineering combining a number of major programming projects into a cross-platform, effective, and unified whole. Moreover it implements a different way of thinking about creating documents; what the authors call “WYSIWYM” (“What You See Is What You Mean).
For a good summary of Lyx see its Wikipedia article.
