Independent US programmer Bill Zeller has developed software that lets users download shared music files using iTunes for Windows.

The software undermines the anti-piracy features developed by Apple to ensure its product is not used to distribute music illegally, although the author warns that the software should not be used in any such illegal fashion.

MyTunes overrides a feature in iTunes that prevents users from downloading music files that are shared over a network, according to information posted on the Cow Pimp Productions Web site where MyTunes has been available for download since October 26.

iTunes allows users to purchase music for download and play that music, in either MP3 or AAC format, on computers running either Mac OS, Windows XP or Windows 2000. Users can listen to music stored on other computers that use iTunes to share music files over a network. However, it does not allow those music files to be downloaded and stored on another computer's hard drive.

The program no longer allows users to share files over the Internet. That feature was stripped from the Mac OS version of iTunes in May, when Apple released iTunes 4.0.1 for Mac OS X, to stop shared music files being copied illegally over the Internet. Current versions of iTunes allow music files to be shared and streamed over a local network.

MyTunes overrides the restriction that prevents users from saving shared music and allows users to save music to the hard drives of their Windows-based PCs, Cow Pimp Productions said. The software differs from other similar programs that allowed music streamed using iTunes to be recorded, it said, noting that MyTunes downloads the original music file.

Neither Zeller – who is also listed as the administrative contact for the Cow Pimp Productions Web site – nor Apple could immediately be reached for comment.

In a statement posted on the Cow Pimp Productions Web site, it recognized the possibility that MyTunes can be used to distribute music files illegally and tells users not to use MyTunes in a manner that involves copyright infringement.

"If you plan on stealing music, do not download this software. If you plan on infringing upon copyrights, do not download this software. Only download this software if you plan on acting responsibly," the Web site said.