Sign ups for the beta are open now for PS3 users. Head to the Playstation Store to spin the wheel and take you chances! I can just taste the brutality now...
Okay, so I may have jumped the gun a little. From Software wasn't clear in their announcement, but at the moment only European PSN accounts are able to submit tickets. There will be a round for NA at some point because they've confirmed that the first round of the beta will start in North America, Europe, and Australia October 12, with a second round on October 27. So there will be NA signups, but when is unknown.
If you're not interested in waiting, people have reported making EU PSN accounts and submitting tickets successfully. Though, make sure the account is created for either Australia, Great Britain, Ireland, New Zealand, or United Arab Emirates. More updates as I hear more info.