The service is only available to Mac users in the US
An online music service for Apple computer users in the United States has sold more than five million songs in the two months since it was launched.
The iTunes Music Store allows customers to download for 99 cents (62p) per song, without subscription fees.
The service is being hailed as the first concrete evidence that computer users are willing to pay for music online rather than download pirated copies for free.
Apple said in a statement that 46% of the songs have been
purchased as albums, and 80% of the 200,000 songs available on the online store have been purchased at least once.
"The iTunes Music Store is changing the way people buy music," said Steve Jobs, Apple's chief executive.
"It clearly illustrates that many customers are hungry for a legal way to acquire their music online."
So far the iTunes service is accessible to fewer than 5% of the world's computer users - those owning an Apple Macintosh and living in the United States.
A Windows version of iTunes is planned for later this year, and an overseas expansion is also on the cards.
Microsoft has indicated that it too wants to launch an online music service for its users.