ArenaNet has announced a pre-purchase date of April 10th. They’ve also announced all of the editions and their contents. More information can be found at the official Link: https://buy.guildwars2.com/
Looks like all pre-purchases will get you 3 things: 1) access to all GW2 Beta Weekend Events, 2) three days of headstart access at release, and 3) a Hero’s Band in game item.
I had to find pricing for the Standard and Digital Deluxe editions at another site. The Guild Wars 2 Collector’s Edition retails at $150 /€149.99/£129.99, the Digital Deluxe at $69.99/€74.99/£64.99 and the Standard Edition at $49.99/€54.99/£49.99. Source: http://www.gamezone.com/products/guild-wars-2/news/pre-order-guild-wars-2-and-get-access-to-all-beta-events