Help! The Ants Are Taking Over!!

In the 20 years we have lived in our home we have had the occasional roach, a mosquito or two, skeeter hawks, daddy long legs, and a few wood spiders, and of course one house fly is too many... But never, NEVER have we had an ant problem... Well, guess what?... This summer, the tiny, little, random, black ants have made their presence WELL known... Argh!

I don't get it... We have NEVER had ants, ever... and these little buggers are frustrating the heck out of me, to the point where I have resorted to chemical war fare, which I really don't like to do with the baby around... I have a friend in South Carolina that swears that Dawn dish soap and warm water directly on their ant hill will take care of the problem, but I have had no such luck... part of the problem is that I can't ever find a trail or where the heck they are coming from! They just appear, randomly, anywhere!! The really curious area was in the MIDDLE of my living room! The kids and I would spend hours on the floor trying to find WHERE they were coming from and going to, and it was almost like they were emerging from right there in the middle of the room...

Now, My sister lives in a newer home, built on what was formerly just a big dirt field. Cement foundation, and ants were pretty much expected every summer. We live in an older home, probably built in the 60's, with wood floors and about a 2-3 foot crawl space underneath, but I'm not sure if these ants could actually, or why they would actually start coming through the middle of the floor. The good news is after pretty much DAILY vacuuming they seemed to have disappeared from the living room, but have reappeared in the dining room, kitchen AND bathroom. Yuck! So far, the bedrooms have been clear...

So, I am open to any and all suggestions... Any ideas?...