We hope you like using that on-screen keyboard on your PS3. Sony confirmed in a statement today that Uncharted 3 will use the Online Pass system introduced earlier this year with Resistance 3. However, the same statement also specified that "Online Pass will be incorporated into... future Sony Computer Entertainment Worldwide Studios games with online functionality."
Similar to EA's Project Ten Dollar and other single-use code programs from other developers, Sony's Online Pass ties multiplayer functionality to the use of, er, a single-use code. While Sony didn't actually spell out Online Pass use "forever and ever," they did include a portentious "We will provide further information in the future."