For a fairly in-your-face example of the difference between procedural and OO, try learning Smalltalk. In Smalltalk, everything, and I mean everything is an object. There are no if-statements or while-loops. You achieve that functionality by sending messages to (a.k.a. invoking methods on) other objects. It really makes your head spin at first, but I think you'll quickly grok what OO is supposed to be.
