Here is a guide from the iPad 2 Wifi section, I'm sure it applies to the GSM and CDMA models:
I broke this cable while replacing the front glass/digitizer of my iPad 2 CDMA. The repair went pretty well, but I accidentally broke the power/volume button ribbon. Replacing the ribbon seems like it will take some work, but not too bad- probably similar to replacing volume cable in iPhone 3GS (which I've done a couple of times.)
I'm not sure if I will go through the trouble, I have a smart case anyway for the power button. Bringing up the soft volume control isn't that hard either. My main fear is getting dust in between the glass and LCD and fiddling with that again. OTOH my front glass is pretty easy to remove now, and doesn't need a heat gun anymore!