Everyone who signed up for the Destiny alpha will have access to it.[Update] Alpha codes going out now.

[LordPhil]

Update: Just received my code, check your emails. 

https://mobile.twitter.com/GuardiansofD/status/476893850678484992

Confirmed by Bungie community manager. 

Registration ends today, June 11, at 11:59PM PST.

Sign up here: http://www.greatnessawaits.com/destiny