CAST offers graduate school internships for MSW candidates:  

Academic year (16-20 hours per week) Sept-May
Requirements: CAST accepts 2nd year MSW candidates from UCLA, USC, CSULB, CSULA, CSUDH, CSUN, Azusa Pacific, and Cal State Fullerton. Bilingual candidates preferred, however not required. Please see your Field Liaison for instructions on potential placement at CAST.