Podcasting allows audio content from one or more user-selected feeds or channels to be automatically downloaded to one's computer as it becomes available, then later transferred to a portable player for consumption at a convenient time and place. It is enjoying phenomenal growth in mainstream society, alongside other Web 2.0 technologies that enable Internet users to author and distribute rich media content quickly and easily. Instead of using the technology for the mere recording and dissemination of lectures and other instructor-centred information, the project reported on in this article focused on enabling students to create their own podcasts for distribution to their peers. The article describes how engaging in the podcasting exercise promoted collaborative knowledge building among the student-producers, as evidenced through focus-group interviewing and an analysis of the products of their shared dialogue and reflection. The findings suggest that the collaborative development of audio learning objects enabling student conceptualisations of disciplinary content to be shared with peers is a powerful way of stimulating both individual and collective learning, as well as supporting social processes of perspective-taking and negotiation of meaning that underpin knowledge creation.