You may also consider a floor potty for the beginning stages, plus you can put it anywhere in the house. We bought a Baby Bjorn Potty Chair (http://www.babybjorn.com/en/American/products/Bathroom/BA...) and my daughter took it immediately (the hole in the toilet scared her). When she was ready to get on the toilet we got her the BB Toilet Trainer (http://www.babybjorn.com/en/American/products/Bathroom/BA...) and a cheap "cushioned" one for our other bathroom. The BB seat was so much nicer because it's contoured, and if my daughter sat on the cushioned one for very long her bottom would get a red ring and she would stick to the cushion.
However, after reading McK4's comment about the built-in seat I think I'm going to try that (dd is 4 and I'm 8 mo pregnant). As nice as the BB seat is, it's really annoying having to take it off when I want to go, remember to put it back on for my daughter, etc.