RealNetworks is set to undercut Apple's iTunes Music Store per-song charge.

RealNetworks is to charge 79 cents for each track sold through its Rhapsody service, which the company is in the process of acquiring. That's 20 cents cheaper than iTunes.

The slight decrease in per-track prices is coupled with a $10 per month subscription that Rhapsody users must now pay.

Speaking to Bloomberg, Gartner analyst Mike McGuire said: "We are so early in the development of this market, it's going to be hard to say whether the Apple approach or the other will be the optimal solution."

Real's Rhapsody service is limited, however. Users can copy their purchases to CDs, but not to portable MP3 players. Subscribers can play songs from the services 3330,000-track strong library, but must pay 79 cents for each of the 200,000 songs available for sale through the service.

Rhapsody supports PCs only, not Macs. Apple plans to release a Windows version of its service later this year, as well as extending its store beyond the US. Roxio last week confirmed its plans to deliver a legal music download service under the Napster brand, which analysts conclude will launch next year.

With existing services also in the frame, the market appears likely to head into a period of intense competition.