Speaking very generally, ordinary people are most likely to deny the existence of free will when they see our deliberations, choices and actions being overridden or bypassed in some way or another. For the folk, or most of them, the dominant idea in attributing free will to themselves and others seems to be a denial of fatalism....Harris appears, then, to think that free will means acting (1) in circumstances such that I could have done otherwise (in the strong, mysterious sense), and (2) by means of a process of deliberation that is entirely conscious. Since, this does not happen, he concludes, we do not have (what he calls) free will....Importantly, the concept of free will that Harris attacks so relentlessly bears little resemblance to either the dominant folk ideas (roughly speaking, that fatalism is false, and that we commonly act without coercion, with adequate time to think) or the technical concept used by most philosophers (we have the capacity to act in such a way that we are morally responsible for our conduct)....Furthermore, the folk (and perhaps philosophers) are not worried only by outright coercion but also by other circumstances, such as whether there was adequate time to think. But where do we draw the line with something like that - for example, how much time is "adequate"? Again, how should we handle such things as compulsions and phobias - are they just another part of our desire-sets, or are they more analogous to external barriers to our actions?...But even if we press such points as hard as possible, folk ideas of free will might survive. Perhaps whether we act freely becomes a matter of judgment and degree, and the question of whether we do so in various particular cases does not have an entirely compelling answer. Nonetheless, it might remain more false than true if we tell the folk, "You do not have free will."
It was hard to pick just a few paragraphs to excerpt, so you'll have to take my word on it when I say that the whole article is interesting. I recommend checking out the related stories in the sidebar as well (he and Sam Harris have a little back-and-forth going).