Is Jacob going to be immortal?

NEW MOON SPOILER!!

Yes Jacob is going to become a werewolf. The Quileute's have many legends of whom they are decended from...Jacob finds out that those legends, are actually true. Jacob becomes a part of the werewolf pack along with Sam Uley, Seth Clearwater, Leah Clearwater, Quil Atarea, Paul, Jared, Embry Call, Brady, Collin,...

Although Jacob does become a werewolf it doesnt exactly mean he is immortal!

any twilight super fan (such as myself) would know that if jacob, for some reason, would want to start growing old again he could! All he would have to do was stop shifting for a time and eventually he would grow old again so techincally he doesn't become immortal.