Gaphor - A UML CASE tool.
Gaphor is rapidly becoming the first really usable CASE tool for GNOME (and Linux in general).
Gaphor is written in Python, which makes it very easy to use (and very easy to extend (and to write ;-).
You can start Gaphor by running the run-gaphor.sh script if your on *nix. Use the run-gaphor.bat file if your under Windows.
Documentation is stored in a different module: gaphor-doc. It can also be read on-line on http://gaphor.sourceforge.net/manual.
Have fun,
Arjan Molenaar <arjanmolenaar@hetnet.nl>