Here are couple things that helped me to find a flat in 2 weeks without knowing german.
1. Get a german friend :) I came to meeting with my german colleague, who was talking mostly with landlord. He was a engineer already leaving in Munich since some months.
2. Send everything possible to your landlord to gain trust I prepared one e-mail with short story what I and my GF are doing in Munich. Add our Facebook, LinkedIn profiles, attached our CVs and for a meeting I took my job contract. His daughter was studying at the same university as my GF - this'd big influence :)
3. Don't wait - Call! I was following all possible websites with flats in Munich. I was not sending e-mails, just calling straight away and after talk sending my "portfolio" (look above - point 2)
Here are some addresses that might be helpful for you guys: