Some argue that man can't have free will if God is All Knowing. If He knows what you're gonna do before you do it, then are you really making the decision or playing puppet? Contrary to popular belief about it, YES IT IS POSSIBLE for mankind to possess free will AND for God to know your every move. How? Let me explain...
There is a large maze on a table. A white lab rat is placed into the maze as a scientist watches. The rat runs thru the maze. It doesn't know where the end is or how to get to it. The scientist observes the mouse. Eventually, the mouse makes it to the end of the maze.
If you're thinking "what does that have to do with the question at hand," you're probably a few slices of bread short of a sandwich. The mouse is you, the scientist is God. Every decision you make, no matter how small, changes your path in life. The outcome of those decisions is unknown to you, just as the mouse doesnt know where each turn will take him. But every possible outcome is known to God. So if you choose to go left, God knows how that will play out. If you choose to go right, God knows where that will lead you also.
So, yes, mankind does have free will and God does know everything.