I attended the Wolverine Fan Event in Times Square today, which included an appearance from the movie's star, Hugh Jackman. He spent a lot of time with the fans and did his best to make sure that everyone who wanted a picture or an autograph got one.
DO NOT READ ANY FURTHER IF YOU DON'T WANT THE IN-CREDITS SCENE SPOILED!!!
The Wolverine features an additional scene that starts rolling not too far into the credits. It picks up two years after Logan has left Japan, and he is currently about to walk through the security checkpoint at the airport. Logan looks up at the monitor above him to see a comercial celebrating Trask Industries and the current advancements in technology the company has made. He advises the airport authorities that he would like to volunteer to be patted down instead of going through the metal detector. Almost immediately after he says this, coins, belt buckles and other metallic objects begin to start floating and shaking on the conveyer belt. It's a tense moment as Logan quickly turns around with his claws outstretched, only to be stopped in mid-turn, unable to move.
The camera pans to Sir Ian McKellan, returning to the franchise as Magneto with his metal manipulating powers restored. Wolverine asks what he wants from him, and Magneto says that there is a grave danger coming that could lead to the extermination of their kind, and that he needs his help. Wolverine asks him why he should trust him. When he finishes the question, everyone around them suddenly freezes (much like the museum scene in X2). Magneto says that he knew Wolverine wouldn't trust him, which is why he didn't come alone. Wolverine looks around in disbelief when he realizes what has happened. The camera pans to a wheelchair moving through the crowded airport as all of the other patrons are still frozen in time.
We then see Sir Patrick Stewart returning to the franchise as Charles Xavier. Wolverine asks how this is even possible (referring to the fact that he watched Xavier seemingly die in X3: The Last Stand). Xavier responds by saying, "As I told you once before, you are not the only one with gifts."
Cut back to credits.
Suffice to say, it was an amazing scene and the two returning veterans received thunderous applause from the audience in the theater.