UMLet is excellent: Not many features, but all the basic ones to draw diagrams, extremely fast to learn (it doesn't even have a help or documentation, and that is great because there is no need for it!) and extremely fast to use.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
I'm trying out UMLet. I successfully downloaded it. It is a .plugin. This is an Eclipse plugn, right? Do I just need to drop it in a folder somewhere to get it to work. Once it's installed, how to you pull up a UML editting window.