Most regulars to this forum actually live in China (or even in Beijing). Taking the tight definition of "expatriate", I think only a few are, including me. We are all happy to answer any questions as far as we can.

Most important for you should be getting in touch with expats (more than one, if possible) of your company that already are in Beijing for a longer period of time. They will have specific information on the procedures, like housing, transport, allowances, how to get involoved and keep updated with the latest happenings, etc. and are -usually- very eager to share and help.
Your company should also have a written guide for newbies to China, I assume.