After it has signed deals with all the four major music labels, Amazon MP3 now claims to have 3.3 million songs from more than 270,000 artists.

Earlier this month, Sony BMG was the latest music label to join Amazon MP3, following similar deals signed by Warner Music, EMI and Universal Music in 2007.

According to Bill Carr, Amazon.com Vice President of Digital Music, the decision to launch international sites was taken after the feedback from the customers.

"We have received thousands of e-mails from Amazon customers around the world asking us when we will make Amazon MP3 available outside of the U.S. They can't wait to choose from the biggest selection of high-quality, low-priced DRM-free MP3 music downloads which play on virtually any music device they own today or will own in the future," Carr said.

Amazon exploits this weakness of iTunes by underlining that every song or album on its MP3 Store is sold in this unprotected format, thus making downloaded tracks compatible with all MP3 players currently on sale, including Apple's iPod and iPhone, Microsoft's Zune, Creative's Zen, SanDisk's Sansa or Toshiba's GigaBeat. Of course, MP3-enabled phones along with PCs and Macs will also be able to play Amazon's content without restrictions.Also the songs bought from Amazon MP3 could be stored on CDs, for personal use.  

Despite Apple's clear dominance in the digital music industry, the presence of DRM software in almost every song sold through its iTunes store is keeping a lot of potential customers away and it definitely frustrates others, who have to buy an iPod to listen their favorite songs.

Also, Amazon MP3 is selling the songs at 89 cents, making the offer even more interesting for potential buyers, because iTunes sells tracks for 10 cents more.