If you like documentation like me!! Well, I guess I am kinda in the dark here since not many people like documentation. This is the tool for you. I am now using it more and more. It is called ArgoUML and you can find it here:

http://argouml.tigris.org/

It can be used either through Java Web Start or a full package download. Give it a try and please DOCUMENT!!!

If you want people to use your software to build software, then document. Make it easy!!