Just to clear a couple of things up.

Some people seem to think that it has been proven that there exist more than 4 dimensions. This is false. Greater than 3 spatial dimensions is speculated due to string theory. Personally, I am quite skeptical of 11 dimensions and a lot of string theory. String theory is one of many schools of thought trying to unify general relativity and quantum field theory. I consider it to be a bit of a fad currently.

Now about time being the fourth dimension. It is in fact a dimension and does play a fundamental role in the geometry of the universe. Space and time are a unified concept as is matter and energy. It's a bit more obvious when you get under the hood and see the mathematics.