Hi Kw,
Welcome to JavaRanch.
Please take a look at the JavaRanch
official policy on displayed names. Your displayed name should be a real name. Can you please update your displayed name to meet this policy? You can change it
here.
There are a few people using Rational Rose, but I believe more people here are using Posideon (
http://www.gentleware.com/).
If you look in the
SCEA FAQ you will find a question titled "What UML tools can be used for the Part II assignment?" - that has links to a few sites which discuss different tools and their benefits.
Regards, Andrew