First of all, if you're in the south you can possibly go outside and pick a tomato, or run down to the vegetable, if you're not, you can possibly get a green tomato in the store or at a farmers market. If you want the tomatoes to be crispier (and less soft on the inside) get one that really green, if you want one with a crust but soft on the inside, go for a tomato starting to turn pink.
You will need:
Enough flour to batter it in (a few tablespoons)
Salt and pepper/seasoning salt/preferred seasoning
Oil to fry them in
First, season the slices of tomato on both sides, then dip them in the flour until its covered, then give it a gentle shake (to get rid of excess) and place them in the pan of hot oil.
They'll look like this at first...
So far everyone I've gotten to try these have loved them (providing they actually liked tomatoes in the first place.) Hopefully if you've never had them you'll become addicted to this summer treat just as I have.