What chapter does Jacob find out hes a werewolf in?

Firstly, the first time Jacob tranforms is in New Moon. Secondly, he is not a werewolf, he is a shape-shifter who is capable of turning into a giant wolf. He is often misinterpreted as a werewolf (by others in the story and fans of the Saga) due to the similarity of his transformation and a werewolves transformation. It is however stated in the story that the wolves are distinctly different from werewolves.