Every song and album is available only in the standard MP3 format using the a high 256Kbps data rate for increased fidelity. These songs can be played on all existing music hardware devices including the iPod, Zune, iRiver, RAZR, etc.... No special software is needed to download the songs (other than a web browser), although Amazon provides a tool you can optionally use to install the songs into your existing iTunes or Windows Media Player music collection. So although Amazon MP3 competes with the iTunes store, it also fits seamlessly into the iTunes application which then syncs with your iPod.
Since the music is free from digital rights management (DRM) restrictions, you can burn it to CD, copy it to your other computers, etc. without having to worry about the content expiring or otherwise becoming unusable in the future. Of course you still have to respect copyright law and just use the music you buy for your own personal enjoyment. But with songs going for as little as $0.89 and albums for $5.99 to $9.99, there's no excuse any more for illegal download sites.
Browsing and buying MP3s from Amazon is easy. 30-second high-quality previews are available for many songs (just click on the little Play button next to the song). Once you've found something you like you can use 1-Click shopping to buy and download.
Many labels are offering their catalog of music for the first time as DRM-free MP3s, including Alligator Records, HighTone Records, Madacy Entertainment, Sanctuary Records, Rounder Records, Righteous Babe Records, Sugar Hill Records, and Trojan Records. The addition of music from Universal came as something of a surprise since up to now they have been a staunch supporter of DRM restrictions. Hopefully it won't be long before DRM is just a bad memory, and all music you buy will be yours to enjoy for years to come.