This looks like an interesting one. A self service podcast promo exchange. They claim to have some kind of java plug in that allows insertion of the promo without editing your mp3 files. Hmmmm. The details are located here. Sounds like a very interesting technology. It could be used to automate the production of entire shows by inserting random (or selected) clips. I think that the folks at Dailysonic are using something like this to insert ads into their shows.

Kiptronic Website