I don’t know why I can’t find any decent instructions on how to podcast. Sure, there’s lots of information on how to actually create and edit an mp3 file to publish, but there’s almost nothing out there that simply instructs on how to actually publish!!!
I found Podcast Research as the most informative site, and even then I had to experiment to see if I was getting too much fluff. Podcast Research is where I got the following code:

Here is our <a href=”http://www.kunefke.us/blog/wp-content/podcast_test.mp3″ title=”podcast_test.mp3″ rel=”enclosure”>test podcast</a>.

I used this code, edited of course, and did a test on this site. I set up iPodder and subscribed to my rss2 feed that is preconfigured for WordPress, and it downloaded the test mp3, with NO problem.
Just in case you’re wondering, my RSS2 feed using WordPress is
http://www.kunefke.us/blog/?feed=rss2
Just copy from there and paste into your RSS Reader
I just wanted to figure out how to podcast to members of my family and church as inexpensively as possible, and this is the way I do it. I hope if you stumbled upon this post, that it helped you do what you need to do.
For information on getting your podcast to the masses, you’ll probably need to look elsewhere, but there is info on that in Podcast Research.
Good Luck!