HMV, which currently has a 25% share of the UK CD market, and Virgin hope to tap into the rapidly growing digital download music market.
Details of HMV Digital, which goes live on Monday September 5 are being unveiled to the media on Thursday.
However, rival Virgin is attempting to steal a march on HMV by launching its Virgin Digital service on Friday.
Virgin has unveiled the details of its digital music download service, which offers consumers 1m tracks from 40p per day and permanent downloads from 79p.
The service, which is available from , includes a digital music store, music club subscription service, streaming radio and management tools for MP3 players. It is the result of a collaboration between Virgin and US digital music provider Music Net.
To celebrate the launch of the service Virgin has planned performances of bands Bloc Party, The Dandy Warhols and The Cribs.
"Virgin Digital UK is an exciting and innovative download service created and designed with the music fan in mind," said Virgin founder Sir Richard Branson.
HMV is already trumpeting its digital service. To promote it, the retailer has forged an unholy alliance between The Who rock legend Roger Daltrey and hugely annoying, but popular, boy-band McFly to perform a cover of The Who's 'My Generation'.
The retailer has lined up a number of artists to play live at its flagship Oxford Street store next week, including Echo & the Bunnymen and Goldie Lookin' Chain. HMV Digital will also be backed with a major ad campaign.
Virgin is being more reticent about its marketing plans. Virgin Digital will offer consumers more than 1m tracks, which they will be able to sample before they buy.
However, iPod users are going to feel left out. They will not be able to use either service because Apple has refused to make the portable music device compatible with the services. In one report, HMV described Apple's decision as "regrettable" but added that "fashion tends to move on".
Although the digital music market only accounts for 2% of all UK music sales, it has doubled over the last 12 months.
HMV Digital has cost 拢10m to develop and is the result of a collaboration with Microsoft and US digital music provider MusicNet.
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