Is it possible for Amarok to synchronize podcast subscriptions with Google Reader so that if I listen to a podcast episode either on my phone (Google Listen) or on my PC (Amarok) it will get marked as listened in both places?

Not currently and it's not a feature we're considering at the moment.

It might be technically possible if google has an API that supports getting the status from Google Reader.

I would be very grateful if anyone wants to implement this and very willing to help figuring out the podcast syncing.

If I remember correctly, the Google listen implementation is an extension of the google reader tool, or at least it can be accessed through your google reader account. Maybe this is planned to change, but I bet that any available APIs function the same.

Enter Akonadi. It doesn't really make sense to keep separate data on rss feeds for amarok only, when we have akonadi around. There has already been talk about extending the google akonadi code, to include access to google reader information. It makes sense to piggy-back on this concept, using a reader (or listen) specific data-source, have akonadi keep it up to date, and then have an amarok plugin that interfaces with akonadi.

Is it ok to have the akonadi dependencies? I can imagine that if the listen code is modularized, then any akonadi dependencies are acceptable, amarok may already have the dependency due to kdelibs dependencies etc (I can't remember where it's at.)