Guild Wars 2 team has officially announced on the Twitter that official Beta Weekend Event invites have just been sent!
We’ve started sending out emails with instructions for where/how to download the Beta client. Thanks for your patience; happy patching!
There is official link on the Guild Wars 2 forum for client download, after login go to Account ->Download Clients link.
You can also use this link: http://cloudfront.guildwars2.com/client/Gw2.exe for download. We can confirm that this link works and you can read more about this on reddit.com