Tips on Volleyball?

sounds like you need a Tamron 18-270 and 1600 or higher ISO.

Well judging from google and using "volleyball olympics 2012" as my reference... copious rear shots are what's needed. I don't have too much of a problem with that of course...
http://bit.ly/THJpKM

In all seriousness though - looking at press shots or otherwise is a good way to start. Then going back to the arena and seeing what you can do with your surroundings to get similar compositions. Like this:
http://500px.com/search?utf8=✓&q=indoor+volleyball
http://www.flickr.com/search/?q=indoor+volleyball&f=hp

It might even be a good idea, since you have the opportunity, to go when a match isn't on and less 'pressure' to scope out good positions and take some test shots and try to be prepared to get the best out of your equipment.

Best of luck!

As both a photographer and a volleyball player I have a few suggestions.

Get low and shoot under the net with a longer lens for defense shots. That way you are below or at the level of players diving or digging the ball.

Blocking has to be shot either from the back of the court so that you face the blocker in a position where the hitter isn't blocking your view of the blocker. Or from the side and inline with the height of the net where you can see how their hands/arms penetrate over the net.

Hitting is the hardest to photograph as you are either shooting from a side view or across the net. I think its cool to shoot vertically down on hitters too, but I doubt you have that option in your gym. If you can sneak close to the game near one of the posts at the side of the net then you can shoot the hitter on the opposite side of the court and still see them in close to frontal view if they are hitting cross court.

In any case it is a difficult sport to shoot, but don't be afraid to get in close or use a long lens to help you... and try and capture just one or two players doing specific things (diving, setting, blocking...). I think you'll find you'll start getting better shots if you focus on one player or skill from a certain view point.

Hope this helps.

1) Anticipate 'Peak Action': For example when someone jumps up - at the very top when they change from moving up to moving down, they stop moving all together for a fraction of second... which coincidentally is what most shutter speeds are. But you gotta be good at anticipating this moment. Waiting to see this moment, then firing the shutter.... well that's too late. You have to start thinking about pushing the button a few moments before the peak. It's not just up and down.... watch a game and observe when players change directions. Every time they change directions is an opportunity.
2) Pre-focus. If the net is in the way, then focus on a spot past the net and turn off AF. When someone is about to enter your pre-focus zone you fire the shutter.
3) As someone said above... don't try to shoot the entire game the whole time. Concentrate on one type of action or one player, and ignore everything else during that time. It takes tremendous self-discipline to not shoot the great moment when you are set-up for specific shot... but your overall average of great shots will go up.
4) GT41 Nails it on the head. Get specific advice from people who know and love the game. There may even be an income possibility here - the players may be willing to part with some cash for great shots of themselves. Or at least invite you to their parties.