Just to give you a visual, what JPG spells out is pretty much the deal. Mark Sher, who rides backside, rides a very long pocket on and Enzo. In a different thread Mark states that he just gets speed and launches off the wake.
Another style, which is probably more prevelant, is the style that is discussed above. You want to start from the back of the pocket to generate the speed necessary to launch into the air. It's the combination of speed and the ollie that gives the greatest air.
It will take some practice, but what you want is about 2 or so pumps from the back of the pocket so that you can hit the lip with as much speed as possible, without drifting too much.
In this picture you can see that James is ripping up towards the lip.