I think Glenn is a mid to late 1st round pick, but im not sure he is a fit for the giants.
He is quite a bit heavier than the rest of the giants linemen, and they generally seem to like the smaller guys who pull/trap better, though Shawn Andrews was about the same size as Glenn.
I think its probably 50/50 at best he is still on the board when the giants pick. Hes a near perfect fit for the steelers, who need help at guard and RT. Also could see the lions, Ravens, and 9ers taking a good look at him.