It really doesn't matter what tomato breed you use but I would suggest using a very large and firm breed (ie no Romas or Cherry tomatoes here).
Flour (add a dash of salt & pepper)
Corn meal (optional- I was currently out)
Milk (just a splash)
Next crack your eggs into one bowl and mix up your flour/salt/pepper (and possibly corn meal) in the second bowl.
While you are preparing the tomatoes for the skillet go ahead and heat your olive oil on medium high. You want a drop of water to sizzle when you flick it in the hot oil.
You then just dip both sides of the sliced green tomato into the egg wash and then cover both sides with the flour mixture.