I've written about AllOfMp3.com before. I can't say other than it's a pirated music site. You can buy mp3's of music of all kinds, from a nice catalog, at ridiculously low prices (like $3 or less for a complete album.)
Some wags have suggested that AllofMp3 proves that people are totally willing to pay for downloaded music as long as the price is right. Yeah, like people are totally willing to pay for a BMW as long as the price is right. Other rumors have been that AllOfMp3 is always one step away from being shut down because the WTO has made closing down of AllOfMp3 a condition for accepting Russia into the organization.
So it's always living on the edge. Here's an extensive FAQ from the site where they explain why they consider themselves legal and not a pirated music site.
It's an interesting thing to watch. Don't ask me how I know, but today the site is up but "Downloading is disabled due to scheduled maintenance." Maybe D-Day is upon us?