This question has been answered more than adequately by Waldo.
However, just for my own amusement I'd like to try and condense the whole 'fact'/'theory' debate.
Religion deals with absolutes – it says that one thing is right and another thing is wrong – one thing is true and another is false. Religion is black and white. In religion, there is often no room for theological or intellectual manoeuvre – the religious text says what it says and that's the end of it. It's what makes religion, religion.
Science, on the other hand, says something subtlety different. When a scientist talks about facts, what he is actually saying is, “To the best of our knowledge, at this time, the observable and repeatability testable data shows that [whatever theory is under discussion] appears to reflect reality”. Science leaves room for manoeuvre.
For example, science tells us why objects fall to earth – it's called Gravitational Theory. However, gravity can also be described as a 'fact'. Why? Because every instrument available to man and every single piece of observed evidence leads inexorably to the conclusion that objects fall towards an object with a greater mass at a mathematically predictable rate.
Even the most obtuse creationist would balk at the suggestion that the 'theory' of gravity is an unproven hypothesis.
Evolution is a theory in the same way that gravity is a theory – all the observed evidence strongly suggests that evolution happens and continues to happen.
Therefore, evolution can be accurately described as both a 'fact' and a 'theory' because the likelihood of it being wrong is infinitesimally small.