I have heard that oatmeal works, but I have never tried it.
I have also heard that if you take a scoop from one anthill and a scoop from another and dump the dirt and ants from Hill A onto Hill B and the dirt and ants from Hill B onto Hill A that they will kill the other ants off. I have never tried that either. As fast as those little buggers move, I'd be afraid to try that! James stuck a broom handle into a fire ant hill once and within seconds the whole thing was covered.
I hate the thought of wasting good Cream of Wheat or oatmeal, but I am going to have to try that.