Recent message board/comment section speculation is correct: Nate Guillory has decided to transfer, effective immediately.
Guillory's decision does not come as much of a surprise. Guillory had committed to no less than three schools last fall, changing from Kansas State to Iowa at the last minute (JUCOs can sign in November) only after he found out there wasn't a returning scholarship halfback. He had to figure it was his spot to lose. Of course, he lost it in magnificent fashion, and probably wasn't going to get much playing time (he wasn't listed on the most recent two-deep, and idle internet speculation was that Jewel Hampton had long since passed him by). Throw in the Wegher commitment from last weekend, and the writing was on the wall.
The good news, of course, is that he decided to transfer before classes began, so he can catch on somewhere else quickly (I don't know how those eligibility rules work, but I would assume it's not much different than the Luke Recker rule, where a player who has never actually played for a school after transferring is not penalized for a second move). Plus, that's one more scholarship open for next year (Iowa only has something like 14 open scholarships for the next recruiting class). There had been speculation that his scholarship was "revoked," but judging from the Ferentz presser today, it seems much more likely that the parties agreed to rescind the letter of intent and go their separate ways.
The BHGP staff wishes Lil' Superstar the best of luck.