Nowadays, there are various legal ways to share music and a range of digital information, practically with anyone around the world. You can share and store music manually with removable devices, or through the web, via streaming or file-sharing websites.

Using removable devices

Share music manually by storing your files (MP3, .WAV or other) into a USB flash drive. You can share these files manually with anyone that has a computer with a USB port, by plugging your flash drive into that computer and transferring the files.

Peer to Peer Sharing

This is a legal way of sharing music through sites that charge you a monthly fee or pay-per-purchase. These type of sites, such as Napster, allow you to share your music with other peers within that Napster network.

Share with Music-Streaming Sites

You can share music by posting it on a personalized website, such as MySpace, Facebook or ReverbNation that allows you share your music with anyone visiting your site, via streaming through a media player.

Share with Download sites

You can upload music for sharing on a personalized template-ready website like ReverbNation.com. This allows you share with anyone visiting your site, by downloading and streaming. You must have the copyright for the music you allow people to download.

The legal aspect

If you are not using one of the legal websites for music sharing, you should only share the music for which you have the authorized permission to share, so you are not violating a copyright law.

Source:

Mashable.com: 10 Ways to Share Music on Twitter

Stanford University: File-Sharing and Copyright Law - How it affects you

More Information:

Dartmouth.edu: Copyright Policy & Guidelines: Peer-to-Peer File Sharing and Copyright law

CreativeCommons.org: About CC Music Sharing License