Song.ly lets you share and discover music links on Twitter.
The service takes song title, searches for it on the Web, and both shortens it for Twitter, as well as packages it in a slick little Flash player. This is especially useful since your recipient can play it back without having to download it first. The service also takes the URL of any MP3 that’s hosted on the Web. In addition to its Web interface Songly has a Firefox add-on that lets you right click to shorten and share any audio file you come across. Song.ly tweets can be played back not only on the Song.ly Web site but also in several Twitter clients.
You can discover new music receiving Song.ly tweets, listening to the Song.ly public timeline, playlists of songs tweeted by a particular user, and playlists of songs with a particular hashtag such as #pop.