Breaking news: Blizzard Entertainment now accepting BlizzCon 2008 beta codes on there website, there is no official statement about which game it going to be Diablo 3 or Starcraft 2, stay tuned for more updates!
If you attended in BlizzCon 2008 you can go register here:
Example – Beta confirmation email
To: xxx xxxxxxx
Date: Sat, Apr 25, 2009 at 1:10 PM
Subject: Beta Signup Confirmation
This eMail is to confirm the address entered for the Blizzard Future Beta Sign-Up.
When the chosen beta test begins in the future, we will eMail this address with further instructions. Please keep this eMail active and make sure to check back — you never know when your invitation will appear!
Thank you for your interest in testing our games — we hope to see you soon!
Here is your signup information: