Just google neuroscience and free will at look at anything from the past decade. (edit: ok, I found a pop sci article pointing in the other direction when I googled, but most of it points to no free will.
http://www.scientificamerican.com/article.cfm?id=finding-free-will)
It's a difficult topic to discuss because it's challenging to convey exactly what you mean and understand exactly what other people mean, but I have never read a description of free will that's compatible with a world that exclusively follows some set of laws of physics (discovered and not yet discovered) that doesn't sound like a rewording of the idea that free will is an illusion.
We don't know all the mechanisms of the brain, but what I'm talking about isn't a theory to cover the gaps in our knowledge. Whatever the mechanisms of consciousness are, there is an arrow of causality. There are 2 entities, your brain and your mind. Your brain is the organ in your skull. Your mind is the one thing you are most certain actually exists; the "I" in "I think therefore I am." You perceive that your mind freely makes decisions and your body acts on that decision. So what drives what? One theory is that the brain is an electrochemical mechanism that obeys the laws of physics (discovered and undiscovered) and through the remarkable complexity of this machine, consciousness arises and with it, the perception that we make choices. This is not free will. Your decisions are driven by the state of the atoms in your skull and the inputs and outputs of your eyes and ears and such. With a perfect knowledge of all of physics and the positions and states of all matter and energy, your decisions could theoretically be predicted. Alternately, if we have free will, our will, that is, our mind is free to make decisions and somehow those decisions impact our brains to make our decisions happen.
If the brain is a mechanism, free will is an illusion. A remarkable illusion. It changes everything about how we perceive our existence and if it is any illusion, there can be no evolutionary benefit to it. I find that to be pretty difficult to digest. Alternately, if the mind drives the brain, if it isn't a slave to the laws of nature, then it's supernatural.