http://www.dogbreedinfo.com/yorkshireterrier.htmhttp://www.dogbreedinfo.com/yorkshireterrier.htmhttp://www.dogbreedinfo.com/yorkshireterrier.htmshapeimage_3_link_0
Dog Breed Information Centerhttp://livepage.apple.com/

This is an excellent site for general information on all breeds.

http://www.akc.org/breeds/yorkshire_terrier/index.cfmhttp://www.akc.org/breeds/yorkshire_terrier/index.cfmhttp://www.akc.org/breeds/yorkshire_terrier/index.cfmshapeimage_6_link_0
American Kennel Associationhttp://www.akc.org/breeds/yorkshire_terrier/index.cfm

The American Kennel Association is the primary registration site recognized worldwide.