First, get yourself some desoldering braid. It is woven copper braid available at electronic supply stores or online. You just heat up the solder with your iron, then touch the braid to the molten solder and the braid will suck it up by capillary action.
Soldering is one of those skills that responds to practice. Get yourself an old circuit board and practice soldering and desoldering before you work for real. A half hour of practice will indicate the amount of heat to use with your iron/gun and make sure to solder to a clean connection. One of those magnifying lights you can mount to the table will really help see those small connections.
As to irons or guns, I have never had much luck with guns. (pistol grip with a trigger). I have too much trouble getting consistent heat, I do much better with a small iron (looks like a big pencil or pen). For most electronics, You will need a very small iron and fine (small diameter) solder.
http://www.youtube.com/watch?v=x0YxEilyQVY is a good tutorial, and will link to other info.