Just go to the website and have at it
Bethesda has just let us know that beta signups are happening right now for The Elder Scrolls Online.
All you have to do is go to www.ElderScrollsOnline.com, sign up, and you'll have a chance to get in. All of the details like dates and time windows for the beta will be given at a later date.
Bethesda also notes that you'll be able to test the "built-in social network" in addition to the game. I just hope it's not overwhelming.
If you're curious to see whether or not it actually upholds the Elder Scrolls name, you can actually find out pretty soon. I'll be right there with you exploring Tamriel.