Websites
The Estate of Sir Arthur Conan Doyle still maintains an official online presence. If anyone out there wants to make a film or TV show about Sherlock Holmes, these are the people to contact about legal stuff.
Many, many people have portrayed Sherlock Holmes on film and television. Here are just a few. We're partial to you-know-who. Hint: Robert Downey, Jr.
The clip at the top of this biographical page includes actual footage of Arthur Conan Doyle talking about Dr. James Bell, his real-life inspiration for the character of Sherlock Holmes.
The Sherlock Holmes Society of London not only unites different fans of the great detective; they also plan awesome field trips. They went to India in 2013 to visit sites mentioned in the Holmes novel The Sign of Four.
The Hound of the Baskervilles makes Dartmoor sound like quite a vacation spot, if you don't mind the occasional killer swamp, fire-breathing dog, or escaped convict.
Fictional Sherlock Holmes has a real address: 221B Baker Street, London, where you can visit stuff based on the Holmes stories. Open nearly every day of the year.
Movies
Before Benedict Cumberbatch, Robert Downey, Jr., or Jeremy Brett came along, the most famous actor to play Sherlock Holmes was probably Basil Rathbone—the star of this adaptation.
Another famous English dude makes it into this adaptation: Christopher Lee, a.k.a. Saruman the White in the Lord of the Rings movies, plays Sir Henry Baskerville. This one is available for streaming.
Honestly, this one is our favorite of the faithful Hound adaptations: Jeremy Brett is a slightly manic Holmes, and Edward Hardwicke is a solid, dependable Watson. Two thumbs up for this one.
This second season episode of the BBC show Sherlock, starring Benedict Cumberbatch (a.k.a. the new villain in Star Trek Into Darkness) and Martin Freeman (a.k.a. Bilbo Baggins in The Hobbit series) is a modern adaptation of The Hound of the Baskervilles. It doesn't stick particularly close to the original story, but it's a hoot (or should we say howl) nonetheless.