There's a TSB on this and some other posts about the pulling problem. The wheel alignment can be perfect and yet the car may still pull in one direction or another. The reason is the tires, your car will "like" some tires better than others and will quit pulling when you find the right combo. Choose a tire with a stiffer sidewall, at work we use dunlops and bridgestones on the Camrys and they tend NOT to pull, with these tires. TSB can be found in this thread too
http://www.toyotanation.com/forum/t176218.html
