"Podcast" is a dirty, dirty word. Like "Web video," it's a simple term for a conceptually simple idea that under the hood is mind-bogglingly complex.
I'm not gonna lecture you on how podcasts work and RSS feeds and XML syntax and all that crap. First, because there are much better resources to learn that stuff than I could crap out here, and more importantly, because it bores me stupid. But suffice to say that while it's trivial to encode a Quicktime into
a format suitable for delivery via podcast, that's not the same as podcasting.
In fact, this is a perfect analogy: A client might ask an editor to deliver a show in such-and-such a format suitable for broadcast on such-and-such cable television network. But what you're being asked to do is to
start up your own television station and broadcast them yourself.
If your client already has a podcast set up, you can deliver your show to him in the appropriate format to go out via that podcast. But we can't tell you what that format is, because there's no single specification; your client will have to provide that information for you. If your client
doesn't already have a podcast, then you have a choice to make. Either you'll choose to give your client above-and-beyond service, which in this case means taking off your editor hat entirely and putting on your computer-nerd hat and learning a whole new thing; or you'll choose to say to your client, "I am not a Web developer, sorry," or words to that effect, and point him in the direction of somebody who actually sets up podcasts for a living.
Sorry if that sounds dickish, but you're careening toward a cliff, and I thought you ought to know it.