What exercises/warmups do T-Nationites do for shoulder flexibility and strength? It takes me a while to warm up my shoulders to snatch, or else if I don't, I'll usually hyper extend my back when I get it overhead (re: not fun).
So far, I've taken to using a 7' PVC pipe and, while keeping my elbows locked out, do conic movements around my head. It helps, but I think there's probably a better way to develop shoulder flexibility and strength.
What do you do to prepare your shoulders for Olympic lifting?