Its not available yet. The PSN has not bee restored in all regions yet.
When it becomes available, you will get a code in your email and you'll need to sign up at the AllClear ID Plus site.
Originally Posted by http://blog.us.playstation.com/2011/05/05/sony-offering-free-allclear-id-plus-identity-theft-protection-in-the-united-states-through-debix-inc/
Sony Computer Entertainment and Sony Network Entertainment International have made arrangements with Debix, Inc., one of the industry’s most reputable identity protection firms, to offer AllClear ID Plus at no cost to PlayStation Network and Qriocity account holders for 12 months from the time an account holder registers for the program.
Please note that we will start sending out activation emails for this program over the next few days, and you will have until June 18th to sign-up and redeem your code. You will need to sign up directly through AllClearID, not on Sony’s websites, and details, including step-by-step instructions for the program, will be emailed to United States PSN and Qriocity Account holders soon.