Host an MP3 stream on Archive.org. Sign up for a free account, then click the "Upload" button in the top left corner of the window. Click the "Share" button, select an MP3 and enter the MP3's information. Click "Share My File(s)." Archive.org creates a "Community Audio" page for your MP3 when the uploading process completes. This page includes a streaming MP3 player. To create an embeddable link for this player, click the "Embed This" button underneath it. Paste the resulting link onto your webpage or blog.
Upload MP3s to Soundcloud. A free Soundcloud account allows you to stream several MP3 files, as long as their total combined length is less than two hours. Click "Upload & Share," then "Choose files." Select an MP3 file, and enter its information. Soundcloud converts your song to an MP3 stream. Click the "Share" button above the streaming player to send an email containing a link to your MP3 or to post it to a social networking site.
Stream your MP3 on ReverbNation, which combines social networking features with MP3 stream hosting. Click on "Upload Song," and click "Browse" to select an MP3. Enter its information into the appropriate fields. Click "Upload Now" to create a stream for the MP3. Once the MP3 has finished uploading, click the drop-down menu next to the "Play" button for the track, and choose "Share." A direct link to the MP3 stream appears at the bottom of the "Share Song" window.