There is some great information available on the internet. Here are a few links to useful sites.

United States
The American Kennel Club The official site of the American Kennel Club. This is the official registry for chows born in the US, calendar for all AKC shows, trials and events and lots of other great information.
The Chow Chow Club Inc. The website of the National Breed Club for Chow Chows. Site includes a comprehensive pedigree database that includes health certifications and photos so you can research your chow's pedigree.
Chow Chow Breed Rescue This is the national site associated with the CCCI. If you want to help a chow in need, this is a great site to begin the process. You could literally save a life - a chow in need's life.
Society for the Preservation of Smooth Chows This is a site that features our wonderful smooth-coated chows.
Other Countries
Canadian Kennel Club The official site of the Canadian Kennel Club, registration organization for chows born in Canada.
Chow's Who Pedigrees, photographs, show wins and lots of useful information for European Chow Chows.
Chow Chow Fanciers of Canada This is the website of the National Breed Club in Canada.
Chow Chow links to cool information presented by Northeast Chow Chow Breeders Association