Dracusis - Skinner links to this site (and several others) so I figured I didn't have to.
Ini - "I really wonder about its usage for Flash" - I know what you mean. "Flash" and "OOP" haven't historically been uttered in the same breath. There were many built in objects (the Date object, the XML object, the MovieClip object...) and methods, but Flash didn't force developers to work object oriented, and, although FlashMX is very capable of object oriented scripting, it still doesn't FORCE the developer to write that way. And since thousands of Flash enthusiasts wouldn't know a namespace from a flower vase, they don't.
That doesn't mean MX isn't perfectly capable of creating classes, utilizing inheritance and incapsulating objects with code interfaces. A number of high profile proponents (two that come to mind because I'm reading the book they wrote are Branden Hall (who also runs the FlashCoders list and the associated Wiki) and Samuel Wan) are dragging us along into these unfamiliar waters. Moock also has excellent material in his 2nd edition.
It's not Java. But it's not shabby, and the fun thing is, after getting exposed to OOP in ActionScript, I'm starting to make sense of the JavaScript posts relating to Classes - the ECMA 262 family relationship is neat! From what I can gather, namespaces still aren't fully supported and require some work arounds, and ActionScript is still a lot looser with datatyping than some other languages, but - not too shabby.
I gather that the big interest in OOP has been spurred by developers who want to build components - these are reusable bits of code that are self-contained and sort of snap on - as such, they NEED to be built in an Object Oriented manner, and since they are very hot now, that's the incentive many have needed.
I guess I've gotten outside the bounds of this JavaScript forum, but ... there seems to be a convergance thing happening and I think it's cool.