I've been waiting for Finding Nemo myself, it's one of my favorite movies. I recall it was originally coming out quite awhile ago and then got cancelled or delayed or something.
I'm not sure what Pixar is waiting for. Sort of following thier Logic, it should of came out with Wall-E, since it was the same director. But they released Cars along with Wall-E. They seemed to do the director link thing with Up, as that is the only common link I can see between it and Monsters, which came out on the same day.
Finding Nemo and The Incredibles are the only Pixar Blu-rays I'm wondering about. I fully expect them to wait for Toy Story 3 to put that series on Blu-Ray, but Nemo and Incredibles...wondering what the heck they are waiting for. Maybe they are going to make them with more new features, and not so much ports from the DVDs like thier past catalog titles have been. Not that I'm complaining, I'll still buy all the Pixar movies on Blu-ray, even if the special features from the DVDs are identical.