Rather than outline all of the potential hiccups, I'll point you to a verbose article about one man's experience with upgrading Beta 2 -> RTM.
Guerilla Install Tactics for Visual Stud... If that doesn't answer your question(s), you can probably go to the vstudio setup group for help:
microsoft.public.vstudio.setup FWIW, I installed the Enterprise Architect version on three machines. One was XP Pro, one was .Net Enterprise Server 3590, and the last was .Net Enterprise Server 3604. All had beta versions of .Net installed, and even though I did not follow the advice of the readme file to the letter, I haven't had any problems on any of the machines.