Please be aware that World of Warcraft Cataclysm is, rumoured to be, starting its Friends and Family Alpha phase from Tuesday 12 January 2010.
This will inevitably cause a large number of spammed fake emails to be sent out by people trying to steal users accounts.
Please rest assured that you will KNOW if you are truly being offered a Friends and Family Alpha because you will personally KNOW someone that works at Blizzard Entertainment.
If you received any email purporting to be offering you a Friends and Family Alpha key please (regardless of what the email may say about not discussing this offer with anyone else) feel free to contact a guild officer.
Blizzard's Fake E-mails from "Blizzard Entertainment" (in the Customer Service Forum) is a good resource to look at to confirm if any emails you are receiving are legitimate or not.