#2 - Oct. 21, 2010, 6:38 p.m.
The e-mail address is legit, Saphiros. It was however only used during StarCraft II beta. At this point we are no longer sending out e-mails using wowbetabilling@blizzard.
Your best option to make sure an e-mail is coming from us, is to check the e-mail headers.
How do I access email header information? -
http://us.blizzard.com/support/article/25133