I've also seen Angry Birds merchandise at Knott's Berry Farm and at countless stores in shopping malls. I think it would make better sense for the folks at Rovio to partner with Zynga or EA, companies, IMO, that are much more adept in the gaming market.
So thats where all those people walking around in Angry Bird shirts at disney came from, I wonder where they got them, don't worry I bought mine at J.C. Pennys.