Challenge: An Omniscient God Can't Exist

Here's a challenge from Infidels.org:

Can God know what it is like to learn? If God is omniscient
(all-knowing), then it seems that he would have to know what it is like
to learn. However, in order to know what it is like to learn, one must
have learned something, which involves moving from a state of
not-knowing to a state of knowing. This entails that at one time we were
in a state of not-knowing a thing that was learned, then experienced
what it is like to learn. But if God is essentially omniscient, he
always is and has been omniscient, so was never in a state of
not-knowing. Because being in a state of not-knowing is necessary to
know what it is like to learn, we would seem to have to say that God
does not know what it is like to learn. But this contradicts the
original claim that he does know this based on his omniscience. Thus, it
seems that God's omniscience generates a contradiction. Consequently an
omniscient God cannot exist.

What do you say? Does the idea of an omniscient God create an unresolvable contradiction? Tell us how you would answer this challenge in the comments below, and then on Thursday Brett will post his video answer.