According to Leonard Nimoy, in JJ Abrams' Trek rejig: "I am Spock, and there is another Spock and there is another Spock. There are a total of three Spocks in the movie and that is all I will say about it."
To be fair, he doesn't really need to say much more - that's a big enough leak to send Trekkies scurrying to their communicator devices.
Trek Movie has an in-depth dissection of the news, and it certainly makes for an interesting read. It seems that it's as we've always believed; if you can't get Shatner, you need at least three Spocks to make up for it.
Source: (Trek Movie)