I got turned on to BackPack from 37signals as a way to better manage lists between multiple people in a collaborative fashion. I really love the Voicenotes addon, too!
Being a typical developer, I figured I'd use the BackPack API to extend the system. I found a nice 4-part article on Coding4Fun that already did the hard work, so now my job got even easier.
The only thing to really note here is that you get the API token from the Accounts page of your BackPack site. After that, things just worked great. I'll extend the code to do things like only display active items, and integrate with the Voicenotes to play the sound file, but really, it seems that 95% of what I wanted to do is already done in this article. Thanks to Michael Campbell for writing the series.