From Mashable:

Recently we brought you a list of free & legal music downloads, but we understand that not everyone wants to eat up space on their hard drive or MP3 player.  So we’ve compiled a list of 30+ awesome streaming music sites we know you’ll enjoy.

Whether you’re interested in general streaming music, mixtapes, music discovery, or more, the Internet offers a plethora of streaming music services. Tell us which are your favorites.

See the List