Reuters reports that Amazon.com, Buy.com, AOL, MusicMatch and even a re-launched Napster could all be in the online music business to compete with Apple’s iTunes Music Store by this fall. “There’s going to be a gold rush in the fall, with a whole bunch of services eyeing the a la carte download market,” said Lee Black of Jupiter Research. “Everybody wants to get it going for Christmas.” The article notes that analysts expect Apple to launch iTunes for Windows by Thanksgiving to spur holiday sales of its iPod. Analysts also say that Amazon.com would be the likeliest to collaborate with Apple on a music service. As previously reported, Buy.com is widely expected to launch its “iMusic” service Tuesday.