More and more tools with UML2 support are emerging. Currently, however, UML 1.x is still dominating the tools market. Some tools are listed on
modelbased.net - UML tools.
An older but thorough review on UML tools (not the UML2 ones) is available on the site of Mario Jeckle (
http://www.jeckle.de/umltools.html) who died last year but whose site is kept alive.