to ATP !
I agree with Elaine about the size of your raised bed... I would consider making a longer bed about 2-3 feet wide, or a couple of beds, something like 2-3 feet wide, with a path in between. (Three feet wide is a comfortable width to work in without having to step into the bed, but 2 feet would probably be wide enough for the tomatoes.) Also as Elaine said, tomatoes need fairly deep soil; can you work up the ground underneath your raised bed so they can put some roots further down? Your tomato plants will also need some support, either cages or stakes; if you stake, then you will need to prune the plants. If you cage, don't use the 'ring-type' cages, in my experience they are nowhere near tall enough and always tip over with the entire tomato plant.
As for varieties to grow in the south -- I'm going to have to defer that to my southern friends here; however, if you have neighbors that garden they may be able to give you some ideas about what varieties do well for them, or your county extension service would also have some advice.
