[dorfsmay]

UML, network diagram, flowchart: http://projects.gnome.org/dia/

Sequence diagram: http://sdedit.sourceforge.net/

Also for the corporate world where only Microsoft tools are an option, I tend to just use MS Word, you can make diagrams that are good enough to get the message across, yet everybody has access to it without requiring a special license.

[ch]

sdedit looks like a really useful tool. Thanks for posting this!

[dorfsmay]

No Problem. I was really impress by the ease of use and output quality.