There isn't a store - but a company that organizes local volleyball leagues. I've been playing in Sand Sports leagues for about 4 years now, and they do a good job.
They provide the referee and they put on a leagues in different area locations such as Pera Club in North Tempe and Pranksters II Bar and Grill in South Scottsdale.
They run 4 and 6 man leagues in difficulty levels ranging from recreational to competitive. Ric runs the show, you will probably talk to him if you call.
Current rates for leagues are:
4 Person: $160 (total for the whole team)
6 Person: $180
The leagues last about 8 weeks and include a double elimination tourney at the end that everyone gets into. I think they can also do private leagues, tourneys, etc.