Cryptic Studios announced on the official Star Trek Online website that the Closed Beta has begun, as of October 22.

Those who signed up need to keep an eye on their email, since Cryptic will be periodically inviting people to join in and share their feedback. Additionally, on the right side of the page on the official site, the "Closed Beta" application graphic will change to indicate if a player has been accepted (it'll read "ACCEPTED" in big, bold letters.) Just remember to login.