Music Oasis is a free music library manager that allows you to download and listen to free music.
However, before you get too excited it should be noted that all of the music on Music Oasis is non-commercial i.e. most of the bands featured aren't big acts that you find on major record labels. That's not to say the music is poor - some of it is quite good but if you're looking for free Coldplay or Britney Spears downloads, look elsewhere.
Music Oasis is arranged by genre, artist and album. The music can be downloaded and stored on your hard drive legally and freely. You can generate playlists, all the songs in the library are DRM free and it's very easy to use. The installation process is very annoying though. Music Oasis tries to install everything from Yahoo toolbars to registry scanners, and its hard to know where you are accepting and declining them.
Music Oasis allows you to search for music via a search bar in the top-right hand corner although since there are no big bands in there, it's not much use. As an extra there is a a 'Radios' section although these merely link to websites such as Shoutcast, Last.fm etc.
Music Oasis is fine if you just want to listen to random non commercial music that you can download legally and freely. If you want big hits by major artists though, you'll be disappointed.