The schedules of summer and fall classes are up on the GSW website, at this link. Note that when registration starts on March 29, you can register for both summer and fall classes. Although there are several summer terms, you can take classes in any of them as long as the times don't overlap.
If you're interested in doing an internship, please read the information on the Psychology/Sociology Department website about the procedures for finding and registering for an internship. Please be aware that you can register for 3, 6, or 9 credits of internship, but that you will need to put in 7 hours per week for every 3 internship credit hours if your internship is in the fall, and 14 hours per week for every 3 credits in the summer. Also, if you are planning on doing an internship in the summer, you must register for it by the end of the pre-registration period (April 16).