Fire ants can actually be quite dangerous if you let them go for too long. Some people may scoff at this, but it is true. They can cause an allergic reaction and if you get enough bites at once you could find yourself in the emergency room or worse. This is why it is best to nip this in the butt and get rid of them as soon as you see even a couple around your home, indoors or out.
To state this more clearly, if you see a few outside. No big deal, however, see a few indoors then you have a problem. Now if you notice a lot outside then you should probably at least thin their numbers if not get rid of them completely because their next step is probably inside your home.
What to Use to Get Rid of Fire Ants
Fire ants make very complex ant hills in which most homemade concoctions will not do the trick. The problem is you have to take out the queen otherwise they will continue breeding and waging war with you. That is why it is best to get a commercial poison for the colony. The best ones will be slow killing poisons, which will give them a chance to spread the chemical to the rest of the colony and kill off more that way. A really good one will also infect their food so that when they go to feed the queen it will get her nice and dead really soon and end your problems.
How to Keep Fire Ants in Check
OK so I am sure you have gathered that you need to find their ant hill first. If you are waiting on a shipment of some decent chemical to kill of the ants then you will probably want to at least thin their numbers so that they can't cause any damage while you wait. Simply boil some water and flood them all out. This will kill a good chunk of them, but will not get rid of them completely. This should impede their progress while you get your hands on some good poison to add to it.
Good Poisons to Use
Fire Ant Control is a good one which is one of the cheapest you can get as well. You simply lay this around your yard, and especially around the mound. They will pick it up for food and feed it to the whole colony, including the queen, and in 24-36 hours you will have some dead ants. Now you shouldn't pour any boiling water on them when you put out this poison as you want them to take it all back and get their fill of the stuff so they all die off for good.