While the OYO is already supported by calibre as it is recognized as an Avant reader, using the default cover setting won't work, so I made a little plugin to better support the OYO. Besides the covers it allows users to remove some metadata files the oyo creates with the books, it adds the proper display name/image, etc.
I already spread it in a german forum
a while ago but I thought I'd post it in the official forum as well so that it might even end up in the official plugin list
Current Version 1.2.8