Apple Computer responded Thursday to the imminent release of software from RealNetworks that allows customers of its Rhapsody online music service to play songs on the Apple iPod, calling Realis move "the tactics and ethics of a hacker" and cautioning users they could be blocked from playing music on the iPod.

In a brief statement, Apple said, "we are stunned that RealNetworks has adopted the tactics and ethics of a hacker to break into the iPod, and we are investigating the implications of their actions under the DMCA (Digital Millennium Copyright Act) and other laws. We strongly caution Real and their customers that when we update our iPod software from time to time it is highly likely that Realis Harmony technology will cease to work with current and future iPods."

On Monday, Real announced its Harmony software that when released will allow Windows users to play music bought and downloaded from its online music store on many portable music players, including the iPod, the company said. Apple has refused to license its Fairplay Digital Rights Management (DRM) technology to any other music download service, but Real said it had found a way around using Fairplay to make its files work on the popular iPod, which Apple says controls 50% of the portable music player industry at present.

RealNetworks has hinted as of late that it is in discussions with other online music services to license Harmony.

A spokeswoman for RealNetworks was not immediately available for comment on the Apple statement to The Mac Observer.