With the beginning of the head start, it's also important to note that all characters in the beta have been deleted. This is par for the course with MMORPG betas, and Crpytic was diligent in keeping everyone informed of this -- so hopefully no one is surprised that their beta toon doesn't exist anymore.
Massively staff has been hard at work preparing guides and other information for you. Everything is available to look at via our new Star Trek Online page. Stay tuned to Massively as the head start progresses and moves into the full release next Tuesday.
Update: From the error page on the STO forums at 2:10 p.m. EST: "Some players may experience difficulties logging into Star Trek Online Right now, we are aware of this issue and working on a resolution."