DrawEA is a project mainly written in C#, it's free.
a little tool to draw finite-state machines
(c) 2006-2008 Andreas Krohn (Hamburger1984 at gmail.com)
a little tool to draw finite-state machines written in C# (also builds and runs using mono - display glitches included)
currently supports deterministic and nondeterministic finite-state machines
a stupid bruteforce input processing/matching is included
feel free to use and/or extend this..