Oh man, I'd love to participate in this. I may not be as relevant to the community as most of ya'll (

) , but I'm familiar with voice chat and wouldn't have much trouble getting set up for this.
The idea about syncing audio up with Audacity is definitely possible, but if you want to go an easier route I have a 25-person Ventrilo server with high quality voice enabled, and we can just record the conversation with the program itself. Of course, the only problem at that point is crosstalk (and could especially be a problem if people are using 56k, no offense Madtom.

)
But to answer the earlier question, you absolutely can use Ventrilo on a Mac, and Skype is available as well, but I'm not as familiar with that program.
Skype doesn't really require much hardware beyond a sound card and yeah, a working microphone. If you aren't sure how to test your mic let me know, and I can try to help you out.