Moon situation for Ramadan 2007 in Chicago IL:
Sept 11th, Moon is too close to the sun to be visible at 7:07pm. No chances of visibility.
Sept 12th, Moon at sunset at 7:05pm.
Bukhari Volume 3, Book 31, Number 133: Narrated Abu Huraira: The Prophet or Abu-l-Qasim said, "Start fasting on seeing the crescent (of Ramadan), and give up fasting on seeing the crescent (of Shawwal), and if the sky is overcast (and you cannot see it), complete thirty days of Sha'ban."
Sept 12th, Moon, 15 mins after sunset at 7:20pm. Low chances of visibility.