Redmond, Washington-based NexTune, operator of an online digital music service, reported Thursday that it has launched the NexTune Music Network and a software update that will allow iTunes users to publish their playlists on the Internet-based music network. Called Composer 1.5, NexTune said the application is tightly integrated with Apple's iTunes music software. The company said users can import their iTunes playlists into Composer and then convert the selections into a music program. In turn, that program can be published on the NexTune Music Network, where other network members can download the program, NexTune said. Network membership and use of its software are free, NexTune added.