See instructions near bottom of this post:
http://forums.whirlpool.net.au/forum-replies-archive.cfm/928786.html
Or just go directly to MP3TAG:
Then make sure that you set these tags:
- ITUNESPODCAST = 1
- ITUNESPODCASTURL = http://anything.example.com/ - but it's important to note that if you want a group of mp3s to appear as episodes of the same podcast make the value of ITUNESPODCASTURL the same in all the files.
- RELEASETIME = 2008-04-01T18:20:00Z (optional but handy for sorting)