Yesterday, I bought the french mag "science et vie" which is the reference for searchers and scientists in France. Well, they had an article about perfect pitch (we call it the Absolute ear in french). And they said that the research about it was finding some things, like 40% if the musicians who were musically trained before 6 had it, and it decreased a lot for each year after that, to reach 5% after 9.
Anyways, they said that some countries (it was mostly asiatic ones) had a speech based on pitches (like if you said something in A it would mean happy, while the same word in D would be sad... pretty cool huh?) well, those countries people all developed a perfect pitch-like ear... So it means it's something that can be developed by anyone, the only thing is to do it before 6... Bummer...