Links

Sherlockian.net
http://sherlockian.net

The Arthur Conan Doyle Collection Lancelyn Green Bequest (at Portsmouth)
http://www.conandoylecollection.co.uk/

Friends of the Arthur Conan Doyle Collection
http://www.acdfriends.org/

Friends of Sherlock Holmes Collections newsletters
https://www.lib.umn.edu/scrbm/holmes/friends-newsletters

The Arthur Conan Doyle Estate Ltd
http://www.conandoyleestate.co.uk/

The Baker Street Babes
http://bakerstreetbabes.com/

I Hear of Sherlock Everywhere (podcast)
http://www.ihearofsherlock.com/

Sherlockology (BBC Sherlock fan site) 
Main: http://www.sherlockology.com/   *possibly down
Tumblr http://sherlockology.tumblr.com/ *not recently updated

The Sherlock Holmes Society of London
http://www.sherlock-holmes.org.uk/

The Baker Street Irregulars
https://bakerstreetirregulars.com/