What UML tools does VSTS have in it?
Sure, it comes with Visio, which does a decent job pretending to be a UML
Modeling tool, but really isn't up to snuff for anything serious.
In my opinion, the suite of WhiteHorse modeling tools that come with VSTS
have promise for future versions, but really aren't worth that much these
days.
Personally, I use (for small and medium projects):
1 - Microsoft Word
2 - Visio
Neither is ideal, but both are enough to get the job done. The original
poster though, asked for "Free", and neither of those products are free
(quite the opposite - they're very expensive!).