The beta hasn't actually been officially announced yet. As of this comment it's ...

jasonlewis on Jan 13, 2013 | parent | context | favorite | on: Laravel 4 Beta released

The beta hasn't actually been officially announced yet. As of this comment it's still in a pre-beta stage. Taylor will announce the beta sometime on Monday, as per the following tweet: https://twitter.com/laravelphp/status/289880193580032001