Did God Create Evil? & Thoughts on Calvinism

Thanks to Rose for the head's up on this excellent blog post on Dr. McArthur's Theodicy.

I think John R.'s comments on Calvinism are excellent. And, I certainly understand his concern with the idea that God created evil, but I do believe He did. God is the only one who can create, right? Though, I do not believe God is the cause of evil. I believe the cause lies within the freewill and natural causes of God's creation.

Colossians 1:16 For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:

I've heard other theologians try to explain how evil came about and that it is merely the opposite of obedience to God. It is the negative of the positive. But that just doesn't ring true to me.

Could I be wrong?