Since my Nexus One phone is pretty handy at scanning all sorts of bar codes, I wondered if someone had written an app so I could just can in the bar codes from books that I have to make a catalog.
An app I found that does this handily is Book Mobile.
In the process of installing and trying it out, I found that Google Books (http://books.google.com/) has a bookshelf feature so that you can add books to your bookshelf. You can categorize them (at least by “shelves”) and easily add books.
The BookMobile app also adds books to your Google Favorites book shelf.