I have an iPod touch 3rd gen 32gb with an unresponsive touch screen. I had hoped to buy a replacement digitizer, and got one ...
It is not removed by rotation. There are two spots holding it in, one on the top (menu) and one on the bottom (play/pause). The one on the bottom is put underneath the rectangular protrusion from the bottom metal bezel (the thing around the dock connector). Once you remove the metal bezel, then the click wheel should just lift out, although like Rick said there is a small amount of glue so you may need to use a spudger.