What one book says doesn't necessarily prove anything. I'm not a sceptic or anything, I'm just saying that there's a lot of books on the subject of 2012 that are full of it, and then there are some that are more factual.
For instance, my Mum recently got a book about all the Mayan prophecies about 2012. The book just provides the translations of prophecies of various events and also talks about the similarities between the Chinese calendar and the Mayan calendar (in terms of it's circular shape and similar dating system).
Besides, the talk of the crystal skulls coming together for a new source of knowledge reminds me of the Edgar Cayce prophecy about some book that is supposed to be found under the Sphinx, which is supposed to provide some knowledge that will help us in different ways like finding a cure for cancer, etc and you know, I don't know if archaeologists are allowed to excavate further at the Giza Plateau, but I certainly haven't heard about anything significant being found (but I guess they wouldn't want the public to know if there was something that could threaten or contradict history or someone in some way). In any case, my money's on that Egyptian guy that they always bring in on TV shows for archaeological debates.
I guess I personally cynical about the story of the crystal skulls as it feels really invented and new (IMHO). Of course, ironically, I'm more a believer of Atlantis once existing and yeah, I can accept an ancient history with aliens involved. I believe that there is life out there. I don't know what to believe about 2012, but nowdays, when I look at the world, with climate change, recession (the strikes at G20), questioning capitalism since there is the extremely rich and the extremely poor still (especially since communism doesn't work), once again questioning religion with New Aestheists and all this new technology, I can't help but feel we are entering a time of change. We're seem to be at this juncture that we have to work out how society is going to work with freedoms of choice and speech. Maybe it's always been like this, I don't know, coz I'm young.