Everyone loves Pandora, and Groove Shark is another music streaming site that is quick and easy to use. You can locate songs by artist or title and play them without even becoming a member, but basic membership is free if you wish to join.
The site allows you to create playlists and listen to the radio and will direct you to Amazon or iTunes if you decide to purchase the song you are streaming. One of the benefits of Groove Shark over many other music streaming sites is that it encompasses genres that are often absent from other services. The band directors love this one for locating concert band recordings!