If you want to learn how to think in oo terms, before moving on to investigate patterns and the like, one book you could check out is "Object-Oriented Programming" by Coad and Nicola. It's been around a while (since 1993) but it's still about, and the basics of oo haven't changed.
Coad is one of the original oo people, along with his colleague Yourdon. And then there are Rumbaugh, Booch, Jacobson, whose work came together -- along with others -- to form UML, etc.
There is also Object-Oriented Analysis and Object-Oriented Design in the same series, but I thing OOP is the one to go for. It's selling for $85 on Amazon.com, so it might be one to track down at a library. At least to start with.
While I like it's approach, it might not be to everyone's taste. Amazon.com's "Look Inside" will give you an idea of what you're letting yourself in for!
http://www.amazon.com/Object-Oriented-Programming-Peter-Coad/dp/013032616X
Did you ever watch Sesame St??
Andy
PS Design Patterns is not a book to start with. Once you get oo, then look at patterns to see how you can reuse designs more efficiently.