SpaceWesterns -- space opera meets horse opera is an online fiction magazine filled with stories that blend themes from western fiction with science fiction, including long-running serials. There's some really lovely stuff here -- the genres mesh surprisingly well at times. They've just reprinted my 1998 story Craphound, the first professional sale I ever made, which is about an alien with a yard-sale jones who discovers that he really, really likes old time cowboy toys. Link

See also: Space Western limerick contest-winners