I read an interview with Monique where she was asked why the characters were still at a Jr. college. She stated that Santa Monica Jr. College was changed to Santa Monica College where her and Kim were pursuing BS degrees. From the Promo's on the UPN website, they are both supposed to be in there final year at Santa Monica College since it is their 4th season.
http://www.upn.com/shows/parkers/about.shtml