Have you discovered Workflowy.com? It's perfect for outlining because you can put books at the highest level of bullets, then chapters inside books, then scenes inside chapters, and you can write detailed descriptions inside the scenes. THEN... and this is the beautiful part... you can collapse levels so all you see is the list of books, or the list of chapters in book 3, or the list of scenes in chapter 27. It's so easy to read what you're looking for.

Cheers,
Michelle