the best way to get rid of ants is also a bit of a pain...you'll need to do a bit of detective work and follow each trail of ants...undoubtedly, the trail will lead to some crack in the wall, likely along the floor....
once you find their entrance points, seal it with some caulk...if you do this for all of them, your ant problem will never be all that bad again...they'll eventually find another crack somewhere, but it'll probably be awhile, and when they do, you only have to take about 5 seconds to repeat the process once...
optionally, if you want to be extra thorough, you can fill the crack with your ant poison of choice...I use one called "Grants Kills Ants"...
as you can see, I used to have a hideous ant problem, haha