I'll step in and cover that. If a being is all-knowing, it will be able to extrapolate all results from whatever it creates. All the uses of our free will would have been known before the moment we were created, and inevitably when you create something and you know what it's going to do, that knowledge will inform your creative process.
In other words, omniscience squelches the possibility of free will through determinism. However, both omnipotence and omniscience in their actual definitions are absent from the Bible. All we see from that is that God knows what we will do before we were born (unless I'm mistaken, it says nothing about God knowing what everyone will do before the act of creation mentioned in Genesis) and that he is very, very powerful.
EDIT: I'd like to add an example of the point the author of that site makes about allowing "justified" evil. Can a good person (or god) allow evil to go unchecked and not be evil himself? A common misconception is that this is impossible, but take the case of a parent, child, and playground bully. If the parent coddles the child and intervenes to stop the bully, often the child will grow up lacking spine and have more difficulties in the long run. While bullying is wrong (or evil, the two words mean the same thing), if the parent allows the child to be bullied and uses it as a lesson about standing up for yourself, the child will likely grow up happier and less likely to be a doormat.
This example, unfortunately, deals with the parent who has limited power to prevent evil, whereas an omnipotent parent would also be able to prevent the child being taken advantage of in the future, and there would be no need for the lesson. A deity would not have this problem.
