[MENTION=1613]grodog[/MENTION] has tons of stuff on his site. Some of it might even be for beginners. I'll let him come here and tell us.
I think that MerricB's two articles on Canonfire! are definitely among the best intros to Greyhawk out there, along with (at the conceptual level), Nitescreed's old "Grey in the Hawk" essay and GVD's style guide follow up (also in the Paizo post). Despite some of Nitescreed's essay's flaws, it's full of good inspirational ideas, much like Montand's "Future of Greyhawk" post from Greytalk ~10 years ago.