I am travelling to Beijing from 3-9 Dec 2012. What is the Temp? Any Snow?

Hi, the average temp then should be about 0C. According to the weather reports over the past years, it may start snowing since the mid-Dec. Anyway, it is dry and cold, so you can prepare some warm clothes.
As for the places of interest, don't worry! Most of them will be open and you can certainly have a good visit.