I've used the granules and I buy them at Marshall Grain in Fort Worth. They have the Fertilome brand that uses spinosad (also an organic gardening tool). Don't broadcast any of these things, they kill beneficial insects also.
http://www.marshallgrain.com/store/F10300%21HA01/Come+%26+Get+It+Fire+Ant+KillerThere are some products with essential oils and with orange oil, I don't know how they work. Avoid any of the products with pyrethrin - they may claim that it is "natural" but it is too deadly to too many creatures (humans included) to be using it. Pyrethrin was used for a while in organic programs, but the evidence came out against it as being simply too toxic. It originally came from chrysanthemums, but now is quite often a synthetic form.