We’re as excited as you are, but the PS4 doesn’t even have a box yet. No price or actual release date is set, outside of Holiday 2013. Relax.
HOWEVER. Should there actually be preorders going live any time soon, you can find them here at Amazon’s PS4 page.
Gamestop already has a “Be the First to Know” page up for email alerts for PowerUp members located here. The page will let people know when preorders go live, but will not be actual preorders.
Good luck. And hold your butts. We’ll find out more at E3.
[Edit: Best Buy has a page up, but it's only the reveal video right now. http://bit.ly/Ydn6R7]