Image from scrawlfx.com
Those who did not go out and buy a copy of Bulletstorm, but still want the Gears 3 beta, are still in luck! When you pre-order a copy of Gears of War 3 at any Gamestop (and put $5 down on your payment), you will receive a Beta code. For those who pre-ordered before this offer, you can still go back to the same gamestop and pick up your code.
The beta will launch April 25th, for the 360 (earlier for those who already have access through Bulletstorm).