One of Harry Turtledove's best stories is freely vailable on Tor's portal:
The House That George Build is available in PDF, HTML, Mobi and ePub. You will have to register (free) to be able to download the story.
Harry Norman Turtledove (born June 14, 1949) is an American novelist, who has produced works in several genres including alternate history, historical fiction, fantasy and science fiction. He has been dubbed "The Master of Alternate History".