We have a big problem with them here in Hawaii, especially in the older housing I am in. Here is what has worked for me:
1) First try to figure out where the buggers are getting in and seal those areas off: Some of the many places are around utility/cable cuts from outside, vents, around windows and of course your doorways. Alot of these places have little holes that can be fixed with some caulk.
2) Look for obvious trails of ants inside. They like to live in walls, and come out by electrical sockets. Other places are under stoves/refrigerators where there always seems to be some food that drops there.
3) Seal up anything that might attract them. Some ants like oil, some like sugar. Some are actually attracted to water. Tupperware or cheap versions work great for food storage. A couple of companies make these clips that work great for sealing cereal bags to keep them out.
4) Get some good quality spray that says it will kill for a certain time period after applied. Spray around baseboards in the kitchen, etc...
5) Ant traps might help under the stove or refrigerator.
6) Lastly, get some outdoor bug spray and spray around the above mentioned areas (windows, doors etc...). Also get the perimeter of the house from the ground up to about a foot on the side walls.