Here is a step by step tutorial on how to host MP3s on Blogspot. These instructions are based on the information from the Google Operating System blog. The basic overview is to upload your MP3 file to Google sites, and then use an embedded Flash audio player from Odeo to make it available to your readers.
- Go to Google Sites at http://sites.google.com/. Sign in to your Google account.

- Give your site a name. Fill out the rest of the information as you see fit. Click Create Site.

- You will be brought to your site page. At the bottom of the page is an Attachments section. Click the little plus sign icon to the left of Attachments, then click the Browse button.

- Browse to your MP3 file and then click Open.
- Wait while Google uploads the file. If you want to, you can also edit the page to include explanatory information about the attachment, but it isn't necessary.
- Once the file is uploaded, right-click on the link to the file under Attachments and select Copy Shortcut.

- Paste the link text into a text editor. Remove anything that appears after ".mp3" in the link text. You should end up with something like this:
http://sites.google.com/site/bluebearrblog/Home/FourSeasonsSpring.mp3 - Now copy the code below, and paste it into your text editor.
Replace the text [MP3 file address] with the actual link to your MP3 file. In the case above, here is what it looks like:
<embed src= "http://www.odeo.com/flash/audio_player_standard_gray.swf" quality="high" width="300" height="52" allowscriptaccess="always"
wmode="transparent" type="application/x-shockwave-flash" flashvars=
"valid_sample_rate=true&external_url=http://sites.google.com/site/bluebearrblog/Home/FourSeasonsSpring.mp3" pluginspage="http://www.macromedia.com/go/getflashplayer"></embed> - Open a new window, and go to Blogger.com. Open up a new post, or edit an old post.
- Once you get to the point where you want the music file to appear, click the Edit HTML link at the top of the screen.
Paste in the text ("<embed>...") from your text editor. Then click on Preview. You should be able to see a music player like the one below.