Nope you just walk on. $10 a court per hour after 2PM. I was shocked. In the summer it's even cheaper.
I didn't inquire about the stadium court but I'm guessing it's nearly impossible. We had a tour and they didn't even have the net up.
"The Pusher" - my new ball machine idea. http://tt.tennis-warehouse.com/showpost.php?p=6764523&postcount=1