I'm new to OO4O and I recently went looking for some books. The only thing I found (that concentrated on OO4O) was a book titled:
"Oracle and Visual Basic Developers Handbook" by Jim Fedynich & others...
I found it on Amazon.com and it is listed as "Out-of-Print - Limited Availability" but I was able to purchase it through one of the Amazon Marketplace booksellers.
Hope this helps..