Bethesda has written an extensive blog post explaining the beta for upcoming MMO The Elder Scrolls Online, in which it is confirmed that invitations for the first beta to involve members of the public (i.e. not just family and friends of the developers) will go out at the end of this month. Those who've been selected for the beta will receive an email including instructions that explain when the beta will take place and how to take part.
At first, the beta will take the form of scheduled play sessions that will generally take place on weekends, a few per month. Those selected to participate will be notified well in advance so that they can make sure they're available. At first, a small proportion of those who have applied for the beta will be invited to take part, but as things progress more people will be invited – especially for AvA and stress testing – and the tests themselves will become longer.
If you're interested in The Elder Scrolls Online, you can still sign up for the beta on the website. There's no guarantee you'll get picked, however, especially not for the initial smaller groups. Participants will be selected based on things like their content preferences, their computer's specs, or even where they live. So although Bethesda says there will be a “broad range” of participants selected, there's no way of ensuring you're one of them. You'll just have to keep an eye on your email inbox and hope for the best!
The Elder Scrolls Online is due to launch for PC and Mac later this year.