When you work out the details, I suggest thinking about one specific and in my important feature as well: I would like to see it that the ones listening to the life-act don't discuss things on the forum until the final chapter is made available via www.zombiepodcast.com. I could imagine that those who cannot participate would be tortured like crazy if they would have to avoid spoilerage and discussions for a week or so, if these are already available on the public space of this forum.
But in order to allow the attendees to discuss things on this board, you may consider a special area on this forum. I know, this would require some administration - like especially getting all the correct user-names of the life-act-audience and giving them access to this specific "VIP-area" of this forum.

Best wishes!
Liam