If one cap is gone replace them all. These parts have a limited lifespan and if one went, the others will follow. You can purchase them at [http://www.digikey.com/|digikey], recommended.
The soldering is not really easy, it's all lead free which requires quite high temperatures but incidently i'm just sitting here in front of an iMac G5 which i succesfully repaired this way. Go for it :-)