OpenCulture: Science Collection. (commercial) Contains free cultural and educational media. Loose affiliation with Stanford University.
Science and Technology Podcasts (U.S. Government) Gathered from various government agencies.
Science in Action (California Academy of Sciences). Many topics covered at a popular level.
Science Update (AAAS). A weekly podcast of current activities in science research.
Sounds of Science (National Academies Press). Each is a 10 minute podcast of a critical issue in current science.
Technology Review (MIT). Podcasts from the magazine.