For now, the plug-in provides seamless access to hundreds of podcasts inside the iTunes shell, with downloads functioning in much the same way that the iTunes music store itself works.
"BadApple is NOT from the Beatles," the bare-bones site reads. "It's also not from Apple Computer Inc. It's definitely not endorsed or approved by Apple. In fact, I'm pretty sure they wouldn't want you to use BadApple."
Podcasting--the practice of recording and distributing MP3 files that can be automatically downloaded and put on digital music players such as the iPod--has in the space of months evolved from a hobbyists' tool to adoption by some of the biggest media companies in the world.
Less than a year old in their current form, podcasts initially were dominated by the often-eccentric recorded ramblings of the high-tech crowd. But they've quickly evolved into a widespread distribution format, with major media companies such as Clear Channel and BusinessWeek jumping onboard.
Apple CEO Steve Jobs announced several weeks ago that the next version of iTunes would have support for creating and distributing podcasts. He demonstrated the capability at the company's developers conference two weeks ago, explaining that the service would let people subscribe to individual broadcasts, and provide a way for podcasters to charge for their productions.
"We see it as the hottest thing going in radio, hotter than anything else in radio," Jobsof Macintosh developers at that event.
At this point, there is no official indication of BadFruit's origin. But a handful of signs seem to link the site to MP3Tunes.com, the online song store opened a few months ago by MP3.com founder Michael Robertson.
Log files created by the software show that it talks to a server hosted by MP3Tunes. Code inside the software package, once downloaded, also show links to MP3Tunes.
An Apple spokeswoman did not immediately return calls for comment.
An MP3Tunes employee said that Robertson was out of the country and unavailable for comment.
Apple is scheduled to add its podcast support in version 4.9 of its iTunes software. Some Web site operators say they're already seeing entries in their logs that indicate test versions of the iTunes 4.9 software are being used to download podcasts.
CNET News.com's Ina Fried contributed to this report.