WIKIPEDIA has a helpful page that has some flaws in citations, however it is worth a read.
Animalia Life is a website with some fabulous photos of Siberian Forest Cats in the wilds of Siberian winter.
Here is the History page from White's Farm's website. Mike is a premier New England area breeder and mentor to other breeders.
It is said that the Russian Siberian first appeared in recorded history around the year 1000. It was represented at the first cat show held in England in the 1700s. During the mid 1980s the Russians began to keep formal breeding records and pedigree information, and to develop a breed standard.
The Siberian first came to the US as an exchange for four American-bred Himalayan kittens. In June of 1990, after over a year of correspondence complicated by the language barrier, inconsistent Russian mail delivery, as well as other problems, Elizabeth Terrell of Baton Rouge, Louisiana was finally able to import three Siberian kittens - one male and two females, and thus start the Starpoint breeding program. At almost the same time David Boehm went to Russia and returned with several Siberians of his own. The first colorpoint Siberians were imported to the United States in 1997 by Dana Osburn of Willowbrook Siberians in California. Elizabeth Terrell also founded the TAIGA Siberian Breed Club in 1991 as a way for new owners and breeders to keep in contact with each other. The club serves multiple purposes; primarily, to protect and promote the breed. It is also a place for the exchange of ideas and information, as well as mentoring new breeders and show participants.
Since then, many other kittens have been imported by many of the American breeders to increase the genetic diversity available.