In order to begin podcasting you will need the following items:
rss feed creation software - preferably FeedForAll :-)
podcasting receiver software to test your podcast
(see our list of partners at http://www.feedforall.com/feedforall-partners.htm for suggestions)
bandwith - copious amounts of inexpensive, reliable bandwith
time - in order to develop a following you will need to consistently release new podcasts.
audio mixing or editing software - for compressing and editing your audio files (generally mp3 files are used)