It depends on what type & price range preschool you are looking for.
Many area churches offer excellent preschool programs at very reasonable rates. The programs are non denominational (anyone can attend) and the curriculum varies. Some schools incl some general Christian education (again not spesific to any 1 religion), some dont. The programs are very popular and fill up fast. Most centers had their enrollment in Jan-March.
I can personally recommend Peach Presbyterian Childrens Center
Peace Presbyterian Children's Center
Ive heard good things about the programs at:
Genesis UMC
Genesis United Methodist Church
Cary Baptist
Preschool - First Baptist Chuch of Cary, NC
St Pauls
St. Paul's Episcopal Church Cary, NC - Preschool
Christ Lutheran
Home Page - Christ the King Early Childhood Center (http://www.christthekingcary.org/ministries/ecc/home.htm - broken link)
Hope Chapel
Hope Chapel - ordinary people, experiencing GOD