Blizzard has announced that 100,000 more Diablo 3 beta invites have been sent out in North America, so if you opted in to beta access with your Battle.net account, you should log in and see if you've gotten a notification. Blizzard warns that phishing activity may increase with this new wave of invites, so take care.
If you weren't one of the lucky one hundred thousand, don't fret: Blizzard promises to send out more invites eventually. You can go back to rolling classesnow!