There was a question about Audacity tutorials in the session yesterday. Audacity is free, open source audio recording and editing software available for Windows, Mac and Linux. Here are a few links:
Audacity Tutorials Page - List of tutorials compiled by Audacity. Contains a link to the users manual too.
Audacity Tutorial For Podcasters - From How To Podcast tutorial site.
You'll find tons more by doing a web search for audacity tutorials.