Literacy Centers
Mrs. McDowell's Literacy Centers for Grades K-1
Mrs. Newingham's Literacy Centers for Grade 2
ABC Literacy Centers
Teaching Heart Literacy Centersfor Grades K-2
The K Crew's Centers and Units for Kindergarten
Linda Holliman's Centers (photos)

Go to http://www.fcrr.org select "for teachers" option, and then look through some of the presentations under the professional development area. There is a treasure-trove of actual ideas for literacy centers at this site that you can actually download and assemble to use in a classroom.