Just a quick notice. If you need a Destiny alpha code, and you pre-ordered at Amazon, check your e-mail. Not sure if it's everyone or random pre-orders, but they're sending out more codes. This also means that a number of people who are already in the alpha should have extra codes to give away.
MOD EDIT: An Amazon pre-order gets you a beta key in July. The alpha codes are being sent out wider than that (likely based on prior video game purchases), no pre-order required.