Disclaimer: What I'm about to say has been argued many times before.
There is no proof that god, allah or any other religious deity exists, period. The only argument that those who belong to the above religions have is what's written down in a book.
The bible states that god created the heavens. Well, really, that's just too simple of a statement to make about such a complex thing as the heavens (in my case, the universe). Science has very conclusive evidence to support the idea of the big bang, and dates the universe to be 13.7 billion years old. Background radiation left over from the big bang is the biggest find since trying to understand how the universe was created. Though rigours tests and computer simulation, etc, science has, in my opinion, closed the book on creationism. (Google search WMAP for more information)
The bible also states that god created the earth. Science has given the earth an age of 4 billion years, and they (scientists) have come to that conclusion through radioactive carbon dating. Creationists age the earth to be 6,000 years old. To me that is just ridiculous, because 1) there have been discoveries of ancient civilizations dating to about 25,000 BCE in Mesoamerica, 2) that completely negates dinosaurs and 3) again, that is just too simple of a statement to make and there is no proof. Scientist's that promote this school of thought argue that radioactive carbon dating is flawed. Well, if it is flawed those same scientists should come up with a system that isn't flawed. The reason they haven't is this: It's not flawed.
Physics aside, there are other schools of thought that are completely independent of each other that seems to go against creationism. Those schools include geology, glaciology and biology.
In geology, consider the continents. Is it not surprising that South America and Africa look like they could fit together like a nice puzzle. The other continents as well. Well, that 'puzzle' is called a super continent, and there have been many over the billions of years of earths existence. The most familiar that comes to mind is Pangea.
...I am off to bed right now, and I have a lot more that I wish to add, so check back later.