OK, i have been having a heck of a time working w/ Project Portfolio Server 2007. There really isn't a lot out there in terms of discussion. I have run into a few things that I will start posting here for others benefit. There are plenty of items I don't know about so if anybody knows good resources, don't hesitate to point them out.
Anyway, one thing I ran into, was how to rename the project classes. When you are creating a project, you define a class for that project. The class defines which workflow the project will follow. They default to CLASS 1, CLASS 2 and CLASS 3. That isn't very helpful for my users. I saw how to link workflows to classes (under workflow management) but the naming of the CLASS es was annoying me.
I eventually found this under Settings->Attribute and Indicator Management -> Attributes defintion. Select to see default attributes. The Attribute is called Project Class.
I renamed mine to '>6 month projects', '2-6 month projects', and '<2>