According to the Twitter account, that according to Major Nelson is tied with Microsoft, we should get beta details very soon. Microsoft PR on the other hand refutes the relationship.
Basically we'll either get an announcement for the "US Beta start date" in the next "24 hours" or we won't. Xbox Live's 1 vs. 100 is a big project for Microsoft, let's hope internal company communication improves by the time it launches.
"US Beta start date will be revealed within the next 24 hours. Stay tuned!" wrote 1vs100XboxLive. Major says 'yes', PR says 'no'. A fine pickle of a mess.