From the TOR website

Originally Posted by
http://www.swtor.com/news/news-article/20100709_002
Game Testing for Star Wars™: The Old Republic™ is underway! Those selected to test will gain access to the game and be able to provide valuable feedback to help us tune particular areas of gameplay and begin the process of balancing and tweaking our content.
Game Testing is an on-going process being rolled out in several phases. These phases began with smaller, more focused tests with community members from North America, and later will expand to other territories. Users selected for the test program will be notified via email with more information on accessing the Game Testing Portal. If you’ve not been chosen yet, you may be selected in the next wave!
If you haven’t signed up already, it’s definitely not too late! If you’re not already a member of the Star Wars: The Old Republic community, click here to become one today! Be sure to check the box to indicate you are interested in becoming a tester. If you’re already a member, go to the Game Testing Portal to begin the sign up process. Note that you must be at least 18 years of age to accept the Game Tester Agreement.
Please keep in mind that there are no guarantees that you will be selected once you have completed the sign-up process. For more information about testing Star Wars: The Old Republic, take time to read the Game Testing FAQ.
We’re looking forward to your help in making Star Wars: The Old Republic a success!
According to G4's "The Feed", the Beta is underway and you can still sign up for it
here
G4 Article text:
"BioWare has announced that game testing is currently underway for their galactic MMO Star Wars: The Old Republic. If you want to take part, but haven’t signed up yet, not to worry. There’s still hope (and none of that old hope either).
To participate, you have to be an Old Republic community member, so if you want in, get over there and
sign up. If you are already a member, but haven’t received your invite yet, just be patient. Worst-case scenario: you don’t get to play your most anticipate game of the year many months before its release…I mean, an invite could be coming shortly.
The first wave of testing will be conducted within North America, but BioWare plans to expand the subsequent phases to other territories as well."
-M-