What is it? 
im gonna guess its a bunch of crap. hawking dissapoints me often. look i can write an immaterial post too!!
wtf is the wave function whatever you said?
About this subject i have only heard some people talk about it. At first I got I little confused because it was going into a contradiction, but after a while I realized that its only a matter of perspective over things, since the small atoms to our entirely Universe and “moreâ€! Let me try to explain.
Lets start by the quantum theory. It´s a theory that “describes†all the possible behaviors and states of a particle, right?! Now lets try to do the same, but instead of only the particles lets make it for the Universe itself. Like I said, it may look a contradiction, but it´s only a matter of perspective. The wave function of the Universe, like the quantum theory, says that there are more then only one Universe ( infinit paralell Universes actually) and that they are all, in some way, all connected each other including with ours. What the theory also says, and now please notice how egocentric some scientists can be (Hawking for that matter), is that there is only one correct Universe, that Universe will be ours and that all the other Universes are incompatible or lifeless because all the others are not stable like the one we are. Our Universe is the only stable because the wave function (which connects all the universes and define them all) exists in more quantity in our Universe! In small words, there are infinit universes, but all of them exist to make our the stable one, or jealosly speaking, that the good parts of each universe are all together on ours to make it “perfect†and stable!
Another way to see it is that our Universe is the only one who have life because he assume the right conditions to make life possible and that all the others have diferent physical laws and that make it not possible to create life (now in my opinion, the physical conditions on other universes may not be good to create life as we know it, but why shouldn’t that create other kinds of life completely diferent from ours??!!)!!!
This wave function of Universes theory reminds me the geocentric theory except that instead of the earth on the center of the Universe, is our Universe the centre of them all! I thought we were making some progresses about our egocentric mind, but afterall we are not.
In conclusion I must agree with Future Man. It´s a completely ridiculous theory in my opinion. Lets wait to see if am wrong or not! 
I´m not sure if the wave function of the Universe is this I said, but I believe I am correct!
Best wishes**
for them to say that there is an infinite number of alternate universes and that ours is the only one with life is ludicrious. if every universe is different in some way and there is an infinite number of universes, then there would be an alternate universe for every possibility conceivable (and inconceivable). say our universe is universe x. if there are an infinite amount of alternate universes, then somewhere there must be a universe that is exactly the same (an infinite number that are exactly the same actually). and there would also have to be not only one, but an infinite number of alternate universes in that are exactly the same, only one particle in a piece of matter is slightly to the left or right. in fact, this is necessary when someone says that the universe is infinite. if the universe is indeed infinitley expansive (in either time, space, or both) then every possibility must be fufilled over that infinite spectrum of time or space an infinite number of times. this is the theory i came up with some time ago in order to explain how an infinite universe is possible. i have yet to develop one that would explain how a finite universe is possible
These theories take QM too far. QM offers no ontological explanations. It deals with probabilities, because of physical limitations in observation of things. This does not mean that things are probabilities, and I hope it never does.