The new technique I've discovered is using a butane torch. Now this is very difficult to do at first, and takes practice. I took apart some old electronics i was throwing out and have been using their boards as practice material.
Basically you want to light the torch and use continuous movement back and forth over the part you're trying to re-solder. Keep the flame about 6 inches away from the part at all times. The trick is to get the perfect spot where you heat the solder up to melting point, but you aren't burning the chip or board. It takes time and patience, and lots of practice.
You also have to be careful of what the board is sitting on. Place is somewhere where the surface can heat up, and there is nothing flammable in the area.
Once you have heated up the solder and it has re-flown, DO NOT TOUCH THE BOARD. step back and give it a few minutes to cool. If you bump the board the slightest bit it can shift the parts on it and make bad connections. Let it sit for a few minutes for the solder to cool and harden.
I'm still working on perfecting this technique and I will be sure to update as I go on.
Let me know you success'/failures with this.