http://blog.ericrice.com/blog/_archives/2005/6/4/909411.html

How to build a 10 minute podcast
The first rule of podcasting is that there are no rules in podcasting. Trust that rule, and you'll have a lot less stress in your life.

I've created guidelines for creating short, organized shows that can help you either get started in podcasting or organize your existing podcast into manageable, predictable chunks. As a society, people have become conditioned over generations to expect certain patterns in radio-like content. Podcasting is no exception. Even if your podcast sounds like radio, the most important piece of the podcasting puzzle is that it's made by everyday folk.

With this model I've created, there is room for flexibility and expandability in the event that you are either missing some of these elements or have longer content (like interviews) that tends to take up more space.

The 10 Minute Podcast Recipe
These are not time codes, they are lengths of time for each segment.

00:10 date/promo/tease/banter/ad
Some believe in identifying the show and the date at the beginning of the podcast. Others like starting off with an endorsement. You can even state the underwriter of the show in ten seconds (think of the public television model). What we had done with many of our older pre-podcast shows, was lead in with banter or commentary that happens before the show officially starts.

QUICK TIP: Stressed about saying 'um' and 'ahh'? Don't be. You're human. Relax. Just don't do it in the intro to your show. You should never, ever, ever, ever have a reason to hesitate when you are saying your name and your show. It's an absolute! Practice saying, "Hello, my name is , and welcome to _, the show about and ___!"
00:20 theme music/intro
If having a theme song feels too 'produced' for you, take note that one thing is certain: everyone needs to know who you are, what your show's name is, what it's about. Creating a theme song or intro gives you an audible sound or brand that gets recognized over and over again. Consistency is key.

00:60 preview
The :60 preview is derived from the old rule of thumb for giving a presentation: Tell them what you're going to tell them (followed by 'tell them' and 'tell them what you told them') This is only 90 seconds into the podcast, and is the only time that needs to be invested if your specific show's topic is not of interest for the listener. After this preview window, a listener will either stay or go. (Note: this pertains to people who automatically download your show as opposed to picking your show a la carte based on the the show notes/show summary posted around your show on your blog or web site.

00:30 ad/promo
If you don't have an advertiser or sponsor, or perhaps don't have an interest in advertising, then use this additional 30 second window for the preview or for your show's content. If you do have a sponsor, use this 30 second window to speak the ad. Only use a pre-produced spot from an advertiser IF YOU ARE COMFORTABLE THAT IT WILL FIT WITH YOUR LISTENERS. Generally speaking, the higher the relevancy or the funnier the advertisement, the less offensive it can be (this is a rule of moderation, which does not accommodate the fringe of advertising-haters).

05:00 small stories/top story
The type of podcast you are making will dictate how you approach this first five minutes. If you have a more linear approach (no set topics, more free-flowing), then start with the little content first--the trivial, the amusing, the less-serious--leading into the main piece of information you are delivering (whether it's an interview, a major comment on current events). In the model of the 10 minute podcast, this space could be filled with just one piece of content.

00:30 IDENTIFY
Take a break. Podcasting is still young, and we're seeing podcast content distributed over real-time channels like satellite and terrestrial radio. In these environments, there is very little time-shifting hardware on the market (note: it is my belief that 'time-shifting' is a term used to describe the pausing and resuming of content that is happening in real-time, and using 'time-shifting' to describe the on-demand nature of podcasting is inaccurate).
Identifying who you are, what the show is, what the email address/phone number is, will help those that might come into your content mid-way. And it's a good, non-intrusive way to take a breath. It helps you get to your point faster and reduces the chances of rambling (unless your show's very nature is to ramble ;-)

02:00 feedback/secondary stories
If you solicit feedback and interaction from your listeners (and I highly encourage you do). If you have secondary content, commentary on something you might cover on a future show, or have something else outside of the episode's main focus, do it in this window.

00:15 thank sponsor
Again, if you don't have a sponsor, then add this to the previous block of time. If you do, be sure to thank them and point people to the sponsor's web site.

00:15 outro
End the show, whether it's by voice or by playing a 'closing theme', something that's similar to your podcast's intro (consistency!).

Congratulations, you've reached the 10 minute mark. If you want to be a little bit more creative and extend the show, add some music. Music provides a nice break between podcasts and gives your listener the ability to keep everything playing while he or she goes for a refill on coffee.

Again, I stress that these are guidelines and not a decree. Have fun and build upon them and do something that feels right for you. YOU know your content and you know WHO is listening. be filled with just one piece of content.

00:30 IDENTIFY
Take a break. Podcasting is still young, and we're seeing podcast content distributed over real-time channels like satellite and terrestrial radio. In these environments, there is very little time-shifting hardware on the market (note: it is my belief that 'time-shifting' is a term used to describe the pausing and resuming of content that is happening in real-time, and using 'time-shifting' to describe the on-demand nature of podcasting is inaccurate).
Identifying who you are, what the show is, what the email address/phone number is, will help those that might come into your content mid-way. And it's a good, non-intrusive way to take a breath. It helps you get to your point faster and reduces the chances of rambling (unless your show's very nature is to ramble ;-)

02:00 feedback/secondary stories
If you solicit feedback and interaction from your listeners (and I highly encourage you do). If you have secondary content, commentary on something you might cover on a future show, or have something else outside of the episode's main focus, do it in this window.

00:15 thank sponsor
Again, if you don't have a sponsor, then add this to the previous block of time. If you do, be sure to thank them and point people to the sponsor's web site.

00:15 outro
End the show, whether it's by voice or by playing a 'closing theme', something that's similar to your podcast's intro (consistency!).

Congratulations, you've reached the 10 minute mark. If you want to be a little bit more creative and extend the show, add some music. Music provides a nice break between podcasts and gives your listener the ability to keep everything playing while he or she goes for a refill on coffee.

Again, I stress that these are guidelines and not a decree. Have fun and build upon them and do something that feels right for you. YOU know your content and you know WHO is listening.