A while back I mentioned the Violet UML editor. My mate Alex from Lexecorp pointed out that StarUML is another freebie:
StarUML is an open source project to develop fast, flexible, extensible, featureful, and freely-available UML/MDA platform running on Win32 platform. The goal of the StarUML project is to build a software modeling tool and also platform that is a compelling replacement of commercial UML tools such as Rational Rose, Together and so on.
It looks slightly out of date, but is still worth remembering.
