I recently completed the first episode of an audio series and posted it online for audiences to listen/download.
Podcast recording has its challenges. You need experienced voice-over actors to perform the script and a sound recordist who knows what sort of sound quality to look out for during the final recording. As trying to find voice-over actors is fairly tricky in my homecity, I've resorted to setting up a website purely to cater for actors specialising in that area as well as sound technicians, audio play writers and musicians.
Podcast production is a lot cheaper than film production and doesn't require as many actors or crew involvement. It also becomes useful for needing actors from interstate/overseas as long as they have good quality recording equipment. I've found that once they have that, they can easily email me the audio files so I can add it to the episode during editing. The only downside is they will not be able to physically audition for any roles and will need to email audio files of monologue set out for auditioning purposes.
Another advantage of podcast production is you don't have to worry about finding the right location for various script settings. A good sound designer and editor can create the ambience of any environment with realism from scratch with various sound effects. My audio series is set 1000 years into the future on a spaceship and various alien planets!
Well, I hope that's given you some idea how a podcast is put together.