Been struggling to find a suitable embeddable audio player for google site. Finally found one. Posting this here for future reference.
Choose “Manage Site” from the “More” menu
Click on “Attachments” (left sidebar), then “Upload” and browse for your saved file (MP3 format)
Open a second tab and edit the page where you want the audio embedded
Copy this URL: http://prac-gadget.googlecode.com/files/google-audio.xml
Choose “Insert –> More Gadgets,” then “Add Gadget by URL” and paste the URL
Switch to the attachments tab, right-click on the MP3 attachment and “Copy Link Location”
Switch back to the Audio Player tab and paste in the URL of your MP3