The Guild Wars 2 official site is www.guildwars.com/en, or just guildwars2.com. It’s the place to go for the shop, where you buy stuff with real life money. They have the links to get and download the game. They have info on all the latest game news and various amounts of information on just about everything in the game. [Guild Wars 2 main page]
They have an official forum too.
And check out the "suggested by the author" links below for more!