Looking forward to the podcast, Tim.
I use Accordance for almost every step of the sermon preparation process. For the sermon itself, though, I continue to use a print manuscript.
I did have a few map slides a number of sermons ago, where I ran some images (from Accordance) in Keynote on my iPad mini, which was connected to the projector. My iPhone was with me in the pulpit, to control the iPad. I had just gotten the iPhone and thought it would be pretty cool.
Unfortunately, while I had thoroughly tested the iPad to iPhone Keynote setup at home, I only tested the iPad to projector part in church beforehand, and not the iPhone to iPad. I hadn't set it all up right... so the projector operator did the slides manually from the iPad and projector. It turned out okay, but was not what I had planned.
So one thing to avoid in using in iPad in preaching (which includes but also goes beyond the Accordance app) is neglecting to do a full dry run of everything, even if you're sure it's going to work! This is conventional wisdom already (i.e., not novel), but it's conventional for a reason!