A friend of mine checked the farms listed and found out they are no longer participating. I'll see what I can do to find some local farms that will allow pick your own.
UPDATE: It seems that liability is a concern for local farmers. One gentleman mentioned that people see a latter and a tree and see a paycheck, but then he did offer for me to come pick a box for free if I wanted. From this conversation I gathered that if you are interested in pick your own, contact the farmers directly, explain your interest in supporting local farmers and they might be willing to help you out. It seems like it's all about asking in the right way.
The Fresno State Organic Farm allows U-Pick as they call it. I will post when the picking is allowed. They give wholesale prices and I was told that generally they pick on Saturday mornings (10am-12pm) twice a semester and three or four times in the summer (8am-10am). They also provide worm composting workshops about 3 times a year. Their website is currently under production.