There is a service at http://mypodcast.com/. It is free for a limited number of podcasts. It is fairly easy to use but it is proprietary in that you can't upload to it with other types of files like audacity.
The GCast http://www.gcast.com is great in that you can dial in via a phone and make an entry.
In terms of getting started, we now have a mobile podcasting lab which includes 15 portable, digital audio recorders for our COV project which can be checked out. I've created an online form you can complete to request checking out the lab. I'd be glad to help you and others facilitate student use of these recorders to complete a classroom project involving recorded audio and digital stories.