This podcast (11.4 MB) may be of intrest to SF fans and RPGers alike. It's a lecture by Allen Steele on worldbuilding given at the Odyssey Writing Workshop. [via SF Signal]
"He talks about common problems in invented settings, such as the homogenous world and the habitable planet that has no atmosphere-generating volcanoes. From designing the solar system to the geography of the planet to the plants and animals, Allen covers the important elements necessary to creating an entire environment."