I just finished the preschool search for my daughter. She will start at White Wing next September. The national accreditation program has a website that you can use to get info on programs (http://www.naeyc.org/families). There are a lot of programs that aren't accredited, which according to a preschool-teaching friend of mine isn't necessarily a bad thing. There were 3 programs I like equally, and picked White Wing because it was the cheapest of the 3. A kindergarten-teaching friend of mine likes Chapel School because its students come to her class the best prepared. I also liked Children's Winter Garden.
Registration stared in January, so don't take too long deciding!