Thanks vsrao.
It is a one day job, if you go to Indian Consulate in NY. Submit the application in the morning and get the new and old PP's same evening. It is upto your convienience. Make sure you have a required docs handy. I've seen quite a fewwithout sufficient document at the consulate.
It is better to carry your old PP and new PP for a while when you are travelling.
Hey, if you feel like getting a new PP before stamping, go for it. I am positive that your new GC stamp will go well with your NEW PP.
Good luck.