Feeling podcastically stupid

Just when I thought I understood podcasts, the whole thing comes and bites me on the backside.

I learned at an event how to make an enhanced podcast using Garageband, so I thought I could just add pictures to a track, export to iTunes and stick it in my ipod. Indeed, Di Dawson's moletv video makes it look as easy as that.
http://moletv.org.uk/watch.aspx?v=MYQJU

Nope.

You have to publish it via iWeb to get a podcast channel and then it seems the only way to make it all work is to submit a podcast to iTunes, which i have done. I have no idea where to find it on the iTunes store, but here's the subscription link which I copied from iTunes when it was helping me to set it up. http://web.me.com/xlearn/Site/Podcast/rss.xml

Now I understand that to make something a podcast, you need to put it somewhere that generates an RSS feed. Initially, I thought, I'll upload the file to posterous.com and subscribe to that feed through iTunes, and surely that will work?

No, again. I can get the audio file ok, but not the pictures (chapters, markers...the thing that makes it an enhanced podcast, I guess)

So the question is, if I wasn't using a Mac, how do I make an enhanced podcast and how do I get that to become a podcast that will show the pictures?