You can host with us or you can setup your own blog that supports podcasting. We recently created a plugin for Wordpress called
Blubrry Powerpress that simplifies podcasting in a wordpress blog. You will have a feed you can use with iTunes either by purchasing
Podcast Services from us or by using a Wordpress blog with
Blubrry Powerpress.
Don't confuse a Wordpress blog that you install yourself with the wordpress.com service. As of current you cannot install the Blubrry Powerpress plugin on wordpress.com.
We also have a free resource available called
PodcastFAQ.com that may be able to assist you with understanding the technical issues surrounding podcasting.