Quote Originally Posted by Selexin
I wonder if Russian mobile operators would be willing to sell a sim card to a foreigner...

When I was in France it was impossible to buy a sim card, they simply denied me their services saying that since I had no permanent registration in the country they were not allowed to open a billing account in my name. So I had to use a corporate sim card (the one owned by the company where I was sent on business).
There is a black market for sim cards and you can always buy one.