If you want just a few seed packets, High Mowing Seed is a good place to look since they have a great selection, good prices, and no shipping fee. I have found that their seeds are high quality.
Renais

Try this source...one of the most extensive sources of tomato varieties available.

http://tatianastomatobase.com/wiki/Main_Page

There are a number of good heirloom seed suppliers, I have been buying from Southern Exposure.

http://www.seedsavers.org/
http://www.southernexposure.com/
http://www.tomatogrowers.com/

Welcome to Central Florida! I have been here for a year and haven't found a local source of quality seedlings (although I'm sure it exists somewhere). I get my tomato seeds from Tatiana's, and everything else from Southern Exposure, but all of the sources listed previously are good. Start with some of the classics, and you can't go wrong.

Elight,
If you are near Leesburg check out Simon Seed. They may have seedlings.

Here is a link that might be useful: Simon Seed

There are many informative discussions about this in the archives.

Get on Facebook and search for Florida Backyard Vegetable Gardener, in Spring Hill, Fl. She has heirloom seedlings that will be ready around Feb. 12.

Thanks for all the suggestions. I've been tied to my desk since Christmas and hope to get back to life soon, and plant some tomatoes!

FWIW, heirloom varieties can be kind of a crap shoot; you never know if they're susceptible to diseases in your FL microclimate until you've put lots of time & effort into them.

I finally (sort of) gave up & found a hybrid, Tomande, that has a lot of heirloom qualities: great taste & sweetness & old-fashioned appearance but also great disease/pest resistance. Plants are very vigorous indeterminates. I found seeds @ the Tomato Growers website - they're not in their catalog, for some reason & I had to do a site search to bring it up.

That said, in the past, I had good results w/ Black Plum & Hillbilly.