Microsoft has opened this up to the public, but there is no guarentee you will be accepted. Go to to this site to signup and see what happens http://www.halo3.com/ More details and Source: http://www.betanews.com/article/Microsoft_Opens_Up_Halo_3_Beta/1165422278 -edit- As EP Pointed out, this is currently only available to the U.S.A/Canada - Europe will be at a later time. Registration takes less than 2 minutes. You need a Windows Live ID, and have the option to signup if you need one. After you sign-in, there is one quick form and that's it! I'll keep you guys posted if/when I receive anything.