Great video tutorials on the basic operation of Audacity
http://www.how-to-podcast-tutorial.com/17-audacity-tutorial.htm
http://www.oldradioworld.com/shows/World_War_II_News_Broadcasts.php
Links to sites with Old Time Radio advertisments
http://www.archive.org/details/VintageRadioCommercials/
http://www.oldtimeradiofans.com/old_radio_commercials/
Free Downloadable Sound Effects
http://www.pacdv.com/sounds/