"The DiscoverEd project is a scalable search of educational resources with a special emphasis on Open Educational Resources (OER). As such, it utilizes a web-wide index, promoting results which have been identified as OER. ccLearn is serving as an aggregation point for other organizations which have identified or produced OER."
for more info.
I'm not sure yet what we need to do to ensure our feed is registered - it is free I think.
John Robertson discusses it briefly in his recent blog post Comparing metadata requirements for OERs (part 1)