How do you develop perfect pitch?

Question

http://www.youtube.com/watch?v=GDRc1vak9rM ---Annie

http://www.youtube.com/watch?v=ikvCHrU1t8s ---grease

Answer 1

I think you are confusing perfect pitch and relative pitch.

Perfect pitch is the ability to sing any note on command, without a reference note. It's an extremely rare ability.

Relative pitch is what I think you are asking about. That is the ability to sing a note based on a reference note, which basically means 'singing in tune'.  A good vocal coach can teach you relative pitch.  

Answer 2

You don't - you either have it or you don't. Most musicians don't and yet they still have fine music careers.  It'd be nice to have but it's really no big deal.

Answer 3

there is no such thing as "perfect" pitch, my dear.

that is just simply the ideal pitch you would like to achieve.

all i can say is just practice