In Facebook there are options to upload videos but no ways of uploading an audio file. If you want to upload an mp3 file and share them with your friends; you should have to upload the file in another server and can share that link in FB. But where to upload the file? Muziboo.com is a website which allows the user to upload the mp3 files and share them in FB.
Logon to www.muziboo.com and register yourself for free. Upload your music and this will create a link for the music file you have uploaded and there is a Facebook link, when clicked on that it will ask you to login to your Facebook account and share the music file. When you see your profile now the music file is shown with a player where your friends can play the file and listen to the music. Best way of sharing the music files in Facebook.