The Problem of Evil (XXVII)

[SteveII]

I don't think a tri-Omni being can itself have free will. If it is omniscient, it can foresee everything it will ever do. If it is omnipotent, it can do otherwise. But if it does otherwise, it was not actually omniscient to begin with. So an omniscient being can only do what it foresees it will do and does not possess free will in any meaningful sense, it can't choose to do other than what it already knows it will do. In effect, all its choices were made instantaneously as soon as it came into existence and can never be changed.

I don't think God has free will. A few things:

1) He would be bound by his nature. For example, Christians believe he is essentially good (could not have lacked that quality) so therefore he could not lie. 
2) As you correctly pointed out, he would have knowledge of his perfectly informed future actions so there would be no way to change his mind 
3) Changing one's mind is rooted in ignorance of something (a reason, a fact, etc.). Since ignorance is not possible (omniscience) there is no catalyst for God to change his mind.