So basically I found link number one, an article that says that the logo for Uncharted 3 was posted on a uncharted 2 facebook page. I couldn't find the logo on an uncharted 2 page there, I did find a page for Uncharted 3.(Link number 3) Also, Link 2 speaks of Gamezine bloggers who noticed Naughty Dog looking for Game designers who are skilled in level layout, high concept object placement(hell if I know what that means) and scripting. They also state that Naughty Dog is requesting character artists with advanced knowledge of human anatomy. It's all pretty conjectural at this point. Nothing that I would suggest as definative, but until confirmation comes along, these might good places to keep an eye on.
1. Rumor: Uncharted 3 confirmed on Facebook, Game logo revealed?
2. Naughty Dog Staffing Up For Uncharted 3? - PushSquare.com
3. Uncharted III | Facebook
And before anybody says anything about there being a topic for this, I already searched for the Uncharted series discussion thread and I couldn't find it.