I have asked the muslims I know personally to tell me about their religion. And this was well before 9-11. Without fail, there is no answer, just huffiness. The most memorable was an Iranian that a classmate married. His response to me was, 'you ask me about my religion when you don't even understand your own.' Talk about judgmental! So, I am no longer interested in any questions or answers to promote understanding. I have found over the many years of my life that neither answers nor understanding will not be forthcoming.
Normally, mosques have "open door"-days several times a year. Even without those days, you can everytime walk into a mosque and speak with an Imam who has an educational background regarding religion. There is no reason, why they would not answer your questions if you do show respect.
You also do not go into a church to have a discourse with a Priest over Monthy Python.