The issue at hand with the free will problem as it pertains to the existance of a god, is the following: if there were a god, he would be omniscient and omnipotent, then he would prevent or not create evil in the world. There is evil in the world, so god must not be omnipotent, or omniscient. If god is not omnipotent or omniscient then he is not god.
Where the free will question comes in is in the omniscient portion of the argument. If God is indeed omniscient then he knows all that has happened, all that is happening, and, most importantly, all that will happen. So if he will know all that is to happen, how much room does that leave for someone to have the freedom to do as he pleases.