I\'ve just compiled the latest Amarok from version control
and I have been looking at the PodCasting feature.

My question is - where are the mp3\'s stored? and does Amarok re-download the mp3 each time I choose to play it?

It\'s not getting stored at all. amaroK is able to play the casts live from the server

Its a work in progress, this hasn\'t been implemented yet.