I just checked to see how Les Klinger's lawsuit was going, and the judge ruled in his favor. Sherlock Holmes and other story material in Doyle's pre-1923 works is in the public domain. Anything that's exclusively in the later stories is still in copyright (in the US) and requires a license to use. All the stories are already in the public domain in other countries.
Hooray! This New York Times article states that the Conan Doyle Estate will appeal the ruling, but for now we have a victory. Thanks to Klinger for being so brave, on behalf of all writers of pastiche and fanfic.