Apple has sold over 15 million iPods worldwide and sales are not fading -- 5.3 million were sold in the first quarter of 2005. The iPod has also spawned a major accessory and peripheral boom (e.g. cases, speakers, and radio transmitters).
Unlike a lot of fads, such as the Hula Hoops or Pet Rocks, iPods actually affect behavior. Duke University saw iPods as a teaching tool and gave each incoming freshmen one, however, it recently stopped this practice (almost all of the incoming students already own one anyway). The iPod is no longer just a sound machine for listening to music and podcasts as it now stores photos, notes, and books.
Recently, a communication technologies class at Marymount Manhattan College created audio guides to nine Museum of Modern Art paintings. They're part of a project on how new technology empowers people to break free of traditional media, in this case the museum's own human guides. You can get them free of charge at MOBS.
So, do iPods have any any value in a corporate training setting? For example, could you place an audio and visual guide of your organization on an iPod and send new hires on a "tour" of their own, rather than having them sit through a PowerPoint presentation? Or perhaps record a step-by-step procedure of a task, along with a few picture and/or notes to an iPod and use it as a training device? Or use a podcast as a lecturing device?