I am a podcaster, and I use libsyn.com. They offer unlimited bandwidth. I started using my own webhost, and quickly crashed my webhost server. You can quickly eat up your bandwidth. I realize you are suggesting just audio but just to give you an idea of my weekly bandwidth:
5000 +/- downloads per week x 180mb quicktime file (mpeg4 video) = 900 gigs per week !!
Not to mention getting all the requests within a short time of releasing.
Your bandwidth may not be that crazy, but you never know, you might get hit with a huge bandwidth bill one month !!
Have fun !!