How the heck do you get an audio file to show up as a "play" button here?

Oddly, I found it more of a hassle to edit together a "podcast" of the book review than doing the video ... but how the hell do you get it to show up as a "playback" bar here?

http://dl.dropbox.com/u/3605052/BTBR-Podcast-Linchpin.mp3

Tags: audio