Londonist Sherlock Holmes Map
We all know that Sherlock Holmes lived at 221b Baker Street now, thanks to The Londonist, we can follow all of the great detective's known movements on Google Maps.
The Londonist have used Map Channels to plot every London location mentioned in Conan Doyle's famous novels. Having plotted Holmes' movements The Londonist have even undertaken a little detective work of their own.
Unsurprisingly, they find that there is a lot of action around the Baker Street area, interestingly however Holmes never once set foot in nearby Soho. There is also a lot amount of action around Crystal Palace and the "reason is elementary when you know that Conan Doyle lived for a time in South Norwood".
If you want to see some of the locations outside of London you can always check out the handy Google Maps provided on Google Books. For example, this page has a map of a all the locations in The Complete Sherlock Holmes Volume One.