First came pirate radio, then Internet radio. But in the past few months a new way of circumventing the big, bad broadcast corporations has emerged: podcasts.

Tune in to these blog-based homemade radio shows and you'll hear any number of things: a weekly hourlong program about board games; a daily amateur photography show hosted by an Australian computer programmer; regular people, unschooled in the ways of radio, talking about anything and everything the way real people talk -- clumsily, with curses, dead air and all.

If you've never heard of a podcast, don't worry. Type "podcast" into the Google search engine and it yields results -- but also asks, "Did you mean: broadcast?"

Well, yes. Sort of. Podcasts are broadcasts in only the loosest sense. They don't use megawatt transmitters to send signals tens or hundreds of miles like terrestrial radio. Listeners can't hear them live because they are prerecorded sound files; they don't stream in real time like Internet radio.

A sort of TiVo for amateur online audio, podcasts are radio-style audio files posted inside blogs as MP3s that can be downloaded to an iPod or other portable player. And they represent the next wave of peer-to-peer content sharing -- not limited by the availability of FM/AM spectrum, untouched by FCC regulation, portable and full of possibility.

An audio extension of written blogs, podcasts are almost exclusively talk at present. They are also almost entirely hosted by tech-savvy "early adopters" who are working out the kinks. But that is changing rapidly as the technology for producing and distributing podcasts becomes easier to use for the technically disinclined.

In September, the only podcast was "Trade Secrets," a daily news-and-technology talk show co-hosted by podcasting's pioneers: former MTV veejay Adam Curry and software developer Dave Winer. Curry is the brain behind iPodder (software that has replaced the time-intensive work of finding and manually downloading podcasts by automatically locating them for the listener); Winer is the developer of the file format that allows podcasts to be found.

"When MTV just started, it was really exciting because here was this new thing. We didn't know the format," said Curry, 40, drawing a parallel between the make-it-up-as-you-go-along early days of MTV and the infancy of podcasting. "Of course, it was mostly, 'I'm totally into this! These guys rock!' But it was pretty honest in the beginning, and I think because podcasts are controlled by no one and everyone can do whatever they want, it's just refreshing."

Four weeks after "Trade Secrets" was born, the number of podcasts had jumped to at least six dozen. Following the lead of "Trade Secrets," in mid-September a handful of Canadian college students launched "Blogosphere Radio," a weekly talk show about what bloggers are blogging about. Late September saw the launch of "Esc From the World!," a tech-support podcast started by New Jersey eighth-grader Matthew Bischoff; "Northwest Noise," an Oregon-based music-and-talk show that's been keeping its eye on Mount St. Helens; and "GeekSpeak," a weekly program about board games coming out of Dallas.

"We could never do this show on radio, because who's going to want to give an hour to board gaming?" says Scott Alden, owner of 1,000-plus games and co-host of "GeekSpeak," a podcast that was downloaded at least 5,200 times in its first two weeks.

Commercial radio broadcasters would never touch such a niche program, especially one that drew just a few thousand listeners. They would never air an unedited, error-prone show hosted by self-described "geeks" or amateurs.

But podcasts don't follow a traditional broadcast model. They follow in the footsteps of blogs, from which podcasts were born. In the blogging world, success isn't measured in market share and ad dollars. It's measured in the personal satisfaction of creative expression and the organic growth of a relatively small audience via word of mouth. Already, that word of mouth is strong. According to Winer, "Trade Secrets'" listenership jumped from 1,000 to 6,000 in a single week.

"One of the reasons that blogging succeeded was it didn't just lower the threshold of publication to zero, it made it as easy as e-mail. Earlier, you could construct a Web site, but construction was complicated. You had to hire a designer. Blogging software eliminated that need," said longtime blogger and Linux Journal senior editor Doc Searls.

In 1999, when Searls first began blogging, he said there were just a couple dozen other bloggers. Five years later, there are at least 4 million. Podcasting, he says, has similar potential.

"IPods and the whole phenomena are a way to route around the failure of commercial radio. If an industry can't keep up with its customers or users, then there are enough enterprising people out there to make up the difference by essentially solving their own problems," he said. "Thank you, Steve Jobs, but these people are going to take it the rest of the way."

With time, it's expected that the rampant tech talk on today's podcasts will yield to the wide-ranging content of blogs. Recently the political podcast "Promiscuous Bullet" and a non-tech show for the "everyman" called "Everyday Joe" have come online. So have a few terrestrial radio programs. Podcasting will also, most likely, branch out to include more music -- a prospect that has some podcast enthusiasts excited and others worried.

"This is something no one saw coming," Curry said. "The Digital Millennium Copyright Act, it doesn't really apply. I think [someone's] going to freak out."