Taylor Lautner WILL continue to play Jacob Black in New Moon. If you didn't know, they were thinking of getting someone else since Jacob is supposed to change so much in New Moon and appear a lot older...however, I'm very glad they decided to stick with Taylor. I'd hate to have two different people from Twilight to New Moon. Taylor did a good job, in my opinion, and if they were worried about New Moon, they should have thought of that BEFORE casting Taylor. So yay!
Official "letter" from the director and Stephenier Meyer can be found on Stephenie's website here!