There are three major Warhammer stores in Tampa.
Armada Games, on 56th, has been around for a while and they have a lot of tables and terrain. I'm not a big fan of their clientele, though. I've been in there on Warhammer night (Tuesday, I think) and the smell was really bad.
I usually play at Anthem Games, on Ehrlich. It's a newer store and they've recently doubled in size and have a fair bit of terrain/tables. The community is closer knit and has a better odor. There's going to be a
40k RTT there on Saturday; you can sign up on their forums.
http://anthem-games.com/Forums/
The other major store in the area is Skull and Bonez. I've never been, but I've heard it's run by a bunch of old warhammer geeks and should therefor have a pretty good community. There's also the Hobbytown USA in Brandon, which I've heard has a sizable warhammer scene.