Some are little basic things, like the hints of wolves showing up on everything from shirts to bowls, or the appropriateness of playing Strauss' "Die Fledermaus" in the Volturi's elevator. Others are a little funkier. Weitz threw in a golden compass nod that you might have spotted, and there are even a few real world twists. For example, a Quileute phrase, "Kwop kilawtley" is said by Jacob before the almost-kiss with Bella, and the phasing of the moon with the title isn't backwards, but rather scientifically accurate.
Granted, these are nothing compared to the Widespread Panic of Willow Power, but really, nothing is. Did you spot all the little nods Weitz threw into New Moon?