eUML2 Studio is a powerful set of tools developped from scratch for Eclipse. These tools are designed specially for developpers to put UML in action at the development level: ensure the software quality and reduce the development time.Requirements
eUML2 is qualified only on Windows 2000/XP/Vista, Linux and MAC OS.
For more information: http://www.soyatec.com/euml2/installation/
Recommend the tutorial