And now there's homework-casting. The author recommends iTunes as a podcatcher, but there's some holes in the process. He mentions that NetNewswire would work, but is not free. Rmail is free, no install, easy to use and I'd be prepared to fix any holes in the model.
http://teaching.mrbelshaw.co.uk/index.php/2006/10/25/homework-casting-using-delicious/
Thanks to Marjolein Hoekstra for the link [play tag with me].