I'm currently putting the finishing touches to Podcast parsing in Totem, so it can be used for some plugins, such as my favourite Quicktime trailers sidebar feature, as well as giving Rhythmbox Atom parsing.
After finishing Atom and RSS parsing support, I set out to add support for itpc and itms links, as used by iTunes, and supported in PenguinTV. I re-discovered the inadequacies of old-style Unix libraries (when they don't work as advertised, at all).
If you live in NYC, or Seattle, and have a Starbucks at hand, you might be able to help with this potentially nice feature. Clicking on the song would add it to a personal wishlist (a feature which would also be useful for streaming radios as well).