
Originally, it was known as an "Internet Rumor" - but it has been made official by the blue's (those that write in blue text within the warcraft forums, aka blizzard employees).
How do you get into the beta? Luck, and a little kissing ass. Actually, no, you may get an invite if you fit the demographic they want. They're looking for a broad range of gamers and raid grouping folks to test out the new content.
(imagine this as the door for closed beta tickets)
How are they selecting this talented group of WoW crackfaces? They're using contest winners, BlizzCon attendees, raiding parties and other guilds and individuals. How do you know if you fit in that category? You'll be told.
They go to you, you don't go to them. If you ask how to get into the beta you will be ignored - they do not have time for WoW fans to beg and pleed to make the beta. So, for most of the gamers, you just will have to wait for the game release. If you are choosen - rejoyce. If you are choosen and belong to 2old2play.com you are about to make many new friends (including me, I want the inside scoop).
Read the offical post here.