Episode of 44 Play on Target deals with the issue of Improv vs. Prep. The website describes the episode as follows:
Welcome to the 44th regular episode of the Play On Target podcast (PLOT for short). Every GM falls somewhere along the pre-session spectrum that has full improvisation at one end and heavy preparation on the other. We discuss where we fall and how the system changes that from game to game. We also give you some advice for finding and working with your level of prep.
Lowell Francis of the Age of Ravens blog is one of the contributors to Play on Target.
This episode presents some of the results to this survey. The podcast raises some fascinating points about the way GMs prep for their game. Prep is a very personal process, so listen to the podcast to learn about how some other GMs work on their game.
The Listening Around series of posts are my suggestions for great podcasts.