I'm working on a project where I have to control air in a cylinder so I am using a needle valve.

The needle valve takes 10 turns to go from full open to full close. I need to be able to turn the valve anywhere between open and close.

I was thinking about using a servo since I would know how much it has turned, but what servo do I need to use? Is there any way to make a servo do a single full rotation and stop, and then repeat this process over and over?

I will be using a microcontroller to create the pulses.

I'm new to servos so any help would be appreciated.

Look at the sailing servos.
http://www.hitecrcd.com/servos/show?name=HS-785HB


But, most of them only go around 2 turns.
You would need some gearing to get your 10 tunrs at the needle.

There is nothing standard that will fit your bill so if you want to use a servo for it you will have to modify one. Check out www.lynxmotion.com for how to modify servos for continous rotation.