Alternative videoconferencing technologies for providing telemedicine via the Internet are described. Background information about how digital video applications have been instantiated using Internet protocols is presented. Specific methods for encoding and decoding video are discussed and video applications that have been tested at the National Library of Medicine are reviewed. This article suggests that no one technology is best and that the appropriateness of a method depends on specific applications. Some technologies, however, have lower, more flexible bandwidth requirements and are more standardized, making them more practical. Still, emerging, yet-to-be-standardized applications offer new capabilities warranting further investigation.