The Halo: Reach beta was scheduled to go down today at an unknown time, but not anymore. Bungie was nice enough to extend the beta for one extra day. The beta will be going down tomorrow, May 20th, at 10AM.
Sounds like it is time to load up on caffeine and pull an all nighter. It could be the last chance you have to play Halo: Reach until its full release later this year.