PHP Classes

Greets, I've gone through the PHP Manual a few times now, reading about classes, but really, what's written there doesn't make a whole lot of sense to me. I know a lot, if not the vast majority, of PHP programmers use classes, so I was wondering if some of you could explain them to me. What are the benefits of using classes? What's the format of a class? I'd like to know things like that and anything else you folks would like to teach me. Thanks Phil