First, I cut the component's lead close to the board. Yes, it wastes the component, but you'll apply less heat while desoldering that would have otherwise traveled into the component. I've had very good luck using a light coat of flux on the pad and picking up the solder with desoldering braid and a 20 watt iron. I've tried other methods before, but this one seems to be least damaging and extremely quick. Anything still remaining in the hole that isn't wicked up by the braid can be gently pushed thru with a dental pick heated by the soldering iron. Most important: clean up any left over flux with alcohol during all steps. After everything is resoldered back in place, clean again. It may look great now, but in a month it will be disgusting. There are also some excellent tutorial videos on youtube that you should watch. Practice makes perfect, you may want to try different methods on a busted vcr or something similar.