Another repost of a popular summer time blog :)
UNCOOKED grits are the old southern way to get rid of fire ants. You just sprinkle the uncooked grits in and around the ant mound. Not too much though, you want them to be inticed, not buried underneath. The trick is trying to get a grit to the Queen of the colony.
The newer way is called Orthene Dust made by Ortho. It comes in a can that is similar to Pringles Potato Chips. It's a tall cylinder with a foil top. DO NOT TAKE THE FOIL TOP OFF! Take a fork and poke some holes in it to make a shaker. Lightly sprinkle (like you're dusting the top of a cake with 10x sugar) on top of and around the mound 4 - 6 inches. You want the ants to walk through it. If it is too caked up or thick, they will not travel through it. Conditions need to be dry outside for this to be effective. And by the way.... it smells really bad, but it works really well!
Should be able to find it in most lawn & garden areas of a store!!