That is one of the basic questions of mankind, I think. Religion is an important part of our culture, no matter which religion it is. But does the fact that we believe in a god really mean this god exists? (Warning: this could be quite a philosophical post!)
Richard Dawkins doesn't think it does. That much is obvious from the various interviews I've read. There is no scientific proof of God's existence. (Of course, the point in believing is not needing proof.)
What I sometimes wonder about, is the question whether that really matters.
First of all, I need to point out my own approach to religion. I'm not very religious. I think there might be some kind of divine being around, but I don't believe in the Christian god as a such (although technically I'm Roman-Catholic). I'm not a follower of any church you might find out there. In fact, I'm highly suspicious of people who tell others what to believe. To me, belief is something highly personal and nobody else can tell me what to believe in.
In Europe, that's not very important. Europeans are not judged by other Europeans based on their belief (well, some might do so secretly, but not openly). Fundamental Christians are almost non-existent over here - or at least such a minority that they can't do a thing. Most European countries might be based on Christianity (though various kinds of it), but that doesn't mean they're Christian in the way a Fundamental Christ in the United States might understand it.
But then, what is belief?
Most people believe in some kind of god (or in more than one, that's what's called polytheism). They believe this god (or these gods) has created the universe, has created mankind and - usually - some special plan for us humans. Some religions have the idea of people being reborn again and again to learn about life while others only give us one chance on this world, before we are judged. (Sometimes I wonder what's worse: coming back as a housefly after a very bad life or spending eternity in hell...)
Still, that doesn't answer the main question. What is belief? The question is not how it manifests itself.
Belief is, most of all, thinking something is true without having any proof - and that's why Dawkins will never really convince firm Christians with his book. A true believer doesn't need proof of the things he believes are true. Belief is self-sufficient.
That brings along the next question. What do we need belief for?
Believing in something seems to be a major human survival trait. By believing what the parents tell it, a child can survive. Animals don't need belief, though, because they have more instincts to help them along. But then, maybe believing what older people tell you, is an instinct. We still don't know.
Belief makes it easier to control large quantities of humans. If you can use a group's belief, you can make them do whatever you want. That's what happens in some countries to this very day - and has happened in most others in the past. You just have to say "god wants you to kill those people" or "god wants you to give me all your money" and they will obey. Tyrants have to put in a lot more hard work for the same results...
On the other hand, for children, belief really is an important thing. If a child can't believe its parents when they tell it something, then who could teach it about what to do to survive? If a father tells his child "don't eat this" or "don't touch that", it's usually because those things are dangerous. And as the child believes all he tells it, it will be safe.
So belief is important, but it can be misused easily (and this has happened in the past).
Religion also brings us straight to "the meaning of life," this fundamental question embedded in the human nature. We like to think our life has some kind of meaning. We like to think we're on this globe for a purpose. And, of course, we like to think we're important.
"God has given this world to us" is a basic principle of the Christian belief. We are in charge and can use the world whatever way we like (and just look what we did with it). With this and the idea of Christianity being the "only true" belief, Christians conquered other people, enslaved the populace, took over their country and in addition thought those conquered and enslaved should be grateful for it (but, to be fair, so did the Moslems as well - and various other religious groups). Genghis Khan had a more difficult approach: he just took the country and said "believe what you want, but don't oppose me." Strangely enough, that worked well.
Biologically speaking, the only "meaning of life" for every living creature is to propagate. But that's not enough to keep the human mind entertained, so we need something else to do with our spare time. So we're making our own "meaning of life" and invent reasons why it's true. And belief is a practical way to make others share our idea of the "meaning of life" and help us to make it come true. That might create a paradise or a hell, based on the ideals of the one starting all of it.
And now back to God. Does God exist?
Scientifically: probably not. It has never been proven. Religiously: yes, without a doubt. What would a religion be without God?
And who is right? That's the question nobody can answer.