The Destiny Beta will be available first on PS3/4.
Eventually the Beta for Bungie’s first multi-platform game under Activision’s banner, Destiny, will be available on a whole bunch of platforms- but the PlayStation family is getting first crack. All you need to do to get in on it is pre-order the game from any participating retailer. After you do that, you’ll get a code printed on your pre-order receipt that you’ll need to input here in order to secure your position as a Beta participant.
The official kick-off date for the Beta hasn’t been announced yet, but you can expect it for the Xbox 360/One, PC and PS3/4 sometime next year- if you’re riding on the PlayStation train though, you should get a nice little bit of lead time before everybody else gets their mitts on Destiny’s world.