Anyhoo, it's currently in a closed Beta, meaning the only way to sign up is to get invited by a friend. This would be in our mutual interest, gentlemen- you get entrance to a site where you can get free stuff just for logging in every day (Seriously, 2 Ptz for logging in.) and I get 2ptz for every friend I refer, up to a maximum of 20. If one can successfully invite 20 friends, you become a "Z-Lister", earning twice as many Ptz for a full year. So of course, if you're interested, try inviting as many of your own friends as possible; it helps you and the site owners.
Example of stuff you can win;
42" TV (3000 ptz)
iPod Touch (600 ptz)
7th Generation Video Games [Wii, PS3, 360 stuff] (100 ptz)
The 'Ptz place', the official page for redeeming your prizes, is still being worked on and you can't get anything for now.
What are the advantages in joining?
Joining earlier would mean having more time to accumulate ptz until the date you can start redeeming them for prizes. Additionally, the prices of things will gradually go up as more people join, so having more ptz, and at an earlier time, is a double-win.
It is seriously completely free?
Yup

Is this gonna be another one of those asshole sites open to US only?
No. Right now, they're not shipping to any countries since they're not officially open yet... but recently, they held a contest where international members outside the United States had a chance to win a laptop; so obviously, international membership is a plan for the future of Lockerz.
How do I sign up?
Post your email in the following format; email(AT)site(DOT)com. I'll invite you within a day.