Noting that the iTunes Music Store is "on a trajectory" to pass Amazon and become the fourth largest reseller of music in the United States, Apple CEO Steve Jobs on Tuesday unveiled iTunes 7. The latest iteration of the software features cleaner navigation, the ability to scroll through the music library by viewing album covers, and more.

iTunes 7 can also update an iPod from within the software, rather than requiring the user to make changes via the Preferences. Gapless playback eliminates the pause between songs that normally flow together, such as many of the selections on Pink Floyd's Dark Side of the Moon. When first installed, the software scans the music library for such music and enables the relevant ones for gapless playbck.

In addition, iTunes 7 will, for free, automatically download missing album covers from the store, assuming the user has an account. Mr. Jobs noted that the store has 3.5 million songs, all of them with album artwork.

iTunes 7 also offers a third view, called Cover Flow, that�s akin to physically flipping through CDs on a rack. Users can change between the three views in iTunes 7 through a three-position switch.

iTunes 7 also introduces the ability to sync content from one computer and upload it from an iPod to another computer, assuming the second machine is authorized with the iTunes Music Store. Each iTMS account can be authorized on up to five computers.

3:36 PM EST, 9/12/06: Updated article with more information.