You might want to try this website to see about preschools in your area:
A parent's decision on which one is the best, is very personalized, and dependent on the teacher and administration for that particular year. Staff changes will affect your view of the experience your child will have at that school. In addition, you might want to consider what you are hoping to achieve with preschool. Learning social skills, identification of colors, letters etc is appropriate. If you expect the preschool to be just childcare then you can get that too, but most real preschools are a couple of hours a day and do not take the place of parent participation in their daily development. I do not recommend heavy academics at the age of 4, but I'm not the parent. You can get that too.