The winners of the Beta Key contest held in Blizzplanet were submited to Blizzard. Give it at least a week or two while Blizzard processes and verify the data. They will at first find out if the data matches their records: Full name, Account Login name, Subscription email. Thereafter, they will start emailing Beta Keys and instructions.
Have fun in the remaining weeks of Closed Beta, and hope you purchase the expansion to rip the goodies in Burning Crusade. Thanks for participating.