Someone on the QB recommend this recently:
http://www.amazon.com/Un-Du-Products...dp/B003TZQPTS/
I haven't had a chance to try it yet myself, but the reviews for it are good.
Edit: Forgot to mention my personal standby -- a hair dryer! Heating the adhesive makes it more sticky and therefore easier to remove. Still might need a little Un-Do or Goo Gone afterwards, but often I can get the entire label and all adhesive off just with heat.