I can't believe that I haven't posted anything on BBC's Sherlock! I've been reading fanfiction, and I've downloaded tons of pics, of Martin Freeman specially but also of Benedict Cumberbatch, and still no post. I realized just now, when trying to check what I had already posted on the subject of Sherlock Holmes to avoid repetition. Well, another day. So, here are some interesting sites I've found while looking for the complete works of Arthur Conan Doyle (at least some of them, when I find whatever I last bookmarked I'll add more).
The Arthur Conan Doyle Encyclopedia: so very comprehensive! Life, works, interviews, adaptations, etc. I found it while looking for The Coming of the Fairies.
The Baker Street wiki: includes all versions of the story.
Arthur Conan Doyle: the official site of his literary estate - news and few other things.
Sherlock Holmes Online: in Spanish, with links to download some works, podcasts, and news.
Read Sherlock!: compiles the Sherlock Holmes canon in an easy-to-read and printer-friendly format.
Sherlock Holmes on the Web - Sherlockian.Net: so many, many links!
The complete Sherlock Holmes Canon: from these pages you can download all the original stories for free, in different formats.
Portal Sherlock Holmes - Wikipedia: as useful as the wiki.
Discovering Sherlock Holmes: a Community Reading Project From Stanford University.
The Sherlock Holmes Society of London: a literary and social Society for study of the life and work of Sherlock Holmes and Dr Watson; events, podcasts and bulletins.
Also, I loved the Downey movies, even if at first I despaired at the casting (only at first, I think).
And also, THE Holmes (Conan Doyle) quote:
When you have eliminated the impossible, whatever remains, however improbable, must be the truth.