I discovered the joy of podcasts a few months ago. Here's a list, in no particular order, of the environmental podcasts that I've enjoyed (Living Planet and BBC's One Planet being my faves). The links take you to the RSS feeds.
Living Planet - 30-minute program on environmental issues from a largely European perspective. "Living Planet looks at new technologies, visits innovative projects and keeps you up-to-date on the state of the earth."
PRI's Living on Earth - "A weekly environmental news and information program."
BBC's One Planet - "Covers environmental, development and agriculture stories, dealing with the impact of humankind on the natural world."
Smart City with Carol Coletta - Urban development and planning issues (no longer broadcasting, but archives available).
NPR's environmental podcast - A collection of environmental stories from many different programs under NPR's umbrella.
NPR's Climate Connections - "How we are shaping climate. How climate is shaping us." In partnership with National Geographic.
Nature - "Features highlighted content from the week's edition of Nature including interviews with the people behind the science, and in-depth commentary and analysis from journalists covering science around the world."
Yale School of Forestry & Environmental Studies - Video podcast.
Science in Action - From the California Academy of Sciences.
OnEarth - From the people at NRDC
Michigan Radio: The Environment Report - Twice-weekly short radio program devoted to environmental issues in the Great Lakes State.
Earthbeat Radio - "An hour-long broadcast providing environmental news and views you won’t hear anywhere else. Syndicated to over 60 stations in the U.S. and Canada."
Have I missed anything? Leave a comment and I'll add it to the list.