Public Knowledge has assembled a great set of resources about orphan works, including an overview, a timeline, and (my personal favorite) a list of myths and facts about orphan works legislation. They’re all worth a look.
Public Knowledge has been very involved in developing the orphan works bills and pushing them through Congress, so its perspective is understandably positive. The resources do a good job of countering the Illustrator’s Partnership arguments against orphan works legislation, but none of them address the criticisms coming from the user side, that these bills are too watered down to be useful. I would be interested to see someone from Public Knowledge reply to some of the concerns raised by Georgia Harper. The bills are moving forward but a lot of committee markup is still to come, and there may still be a chance for the final version to satisfy librarians and other user advocates.