there are several common styles of desoldering tools commonly available that allow the use of a regular Soldering Iron for desoldering:

• Plunger-style tools use a spring-loaded syringe to suck molten solder away from a joint (I personally have yet to find one of these that works terribly well)
• Bulb-style tools have a rubber bulb that can be squished/let go to suck away solder. (I had a red one from Rat Shack and it worked ok. Having to pump it sucked, and made it easy to blow solder into a joint instead of sucking it away.)

You can make a superior DIY desoldering tool by cutting a bulb-style sucker in half and duct-taping it to a vacuum cleaner. Not having to pump the bulb rocks.