gpodder.net is perfect for this kind of thing. The only problem is that the iTunes database is encrypted or at least not documented (I haven't looked into it myself, so I don't know the details), so there is really no way for us to write a gpodder.net client that synchronizes with iTunes. If you find a way to read the playback position from iTunes and to write a new playback position into iTunes, I'll be happy to provide you with the details on how to integrate this with gpodder.net. Once the information is synchronized to/from gpodder.net, the Maemo 5 version of gPodder will take care of automatically updating the info.