UMLet is an open-source Java tool for rapidly drawing UML diagrams with a light-weight, pop-up-free user interface.

UMLet lets you draw diagram sketches fast; export diagrams to eps, pdf, jpg, svg, and system clipboard; share diagrams using Eclipse 3; and create your own custom graphical elements.

URL: http://qse.ifs.tuwien.ac.at/~auer/umlet/
Licence: GPL