1) Start on the side of the wheel oppposite the stem.
2) Pinch both side of the tire together as you work it on the rim (pinching give you a little more slack).
3) Work as much of the tire on the rim as you can by hand.
4) Use the valve stem to push the tube away fron the rim.
5) Insert tire lever to pop on the last little bit.

This method allows use of a tire lever without pinching the tube. Also, using the heel of your hands (with cycling or other gloves on), and rolling the last little bit often works. When all else fails I get my wife's help and we double team it!