We just posted our first podcasts this week. All I did was edit the sermon in Audacity and then follow the instructions on the Apple website. I copied their example feed and just changed all the appropriate sections. The instructions explained all of the sections and also showed the correct way to enter things like ampersands and quotation marks. I worked out pretty well for us.
ML
You can check out our podcast here:
http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=275229130 
P.S. The music for the intro & extro is a freebie from Digital Juice!