Jamendo is a portal where artists can upload and share their music. The files/songs are available for gratis and libre download to the public (licensed under Creative Commons licenses). So you can download any files for your personal use, but for commercial use or derivative works, it depends on the album license, but you can easily see what the license is on the album page.
For example, you can see this album of Silence, called Encre. And on the right you’ll see Your rights on this album, and this tells you what you can or cannot do with this album. Pretty neat 🙂