Video: We've covered all kinds of different ways to learn how to solder, but desoldering is a totally different beast. Adafruit explains how to do it. Adafruit walks you through using a solder sucker, solder wick and Chip Quik. Desoldering certainly isn't a common of a practice as soldering, but it's still a useful skill to learn, especially if you're in the habit of taking apart electronics.
Collin's Lab [YouTube]