To prevent unscrupulous users from making copies of the songs, each digital file on Rhapsody is encoded with Janus -- a so-called "digital rights management" technology provided by Microsoft.
Rob Glaser, RealNetwork's founder and chief executive officer, said the move to offer free listening is designed to entice the digital music fans who still balk at paying for online music.
"Essentially, we've taken away the barrier of, putting your charge card in to use it," said Glaser. "Now all you have to do is download the software and you're off to the races."
Industry watchers note that RealNetwork's latest announcement could also help lure more music fans to legal online music services -- including Rhapsody's own $10 per month unlimited music service.
However, detractors note that while Rhapsody's free plan might be easy on the wallet, it's not a clear slam-dunk. For example, only digital music players that support Microsoft's Janus technology will be able to access Rhapsody's tunes. That means the growing number of Apple iPod owners will probably stick to Apple's iTunes service.
-- Donna Renae, ABC News
Cybershake is produced for ABC News Radio by Andrea J. Smith.