Audacity (for Windows and Mac)
Bark Farcas, Secrets of Podcasting: Using Garageband and Audacity to record podcasts
Audacity tutorial: How to Podcast
About: Setting up Audacity to record podcasts
Recording Skype calls with Audacity
Bran Fountain, Discovery Education: PP presentation on using Audacity
Kent State University Library: Written script for an Audacity production