There's a new service that's currently in beta and lets bloggers create their own talk radio shows. It's called BlogTalkRadio, although I thought the concept was actually invented many years ago and has gone by the name "podcasting."
OK, that wasn't the nicest thing to say... Actually, BlogTalkRadio is indeed much more than podcasting. Podcasting is more of a one-way communication whereas BlogTalkRadio is very much two-way; listeners can call in, ask questions, etc. Although the service is intended to "extend the blog", anyone with an Internet connection and a phone can become a host and there's no charge. In fact, you might even be able to make a few bucks if your show becomes popular. See this FAQ page for more details. You might also want to read this post by Stowe Boyd if you're thinking about starting your own show.