Pcc
Jeet,
you have to get in touch with Indian Consulate in USA. You have to find out which Consulate's jurisdiction you call under. Do a google seach "Indian Embassy | Consulate, USA". That should throw up a list of links on Indian Embassy and Consulates in USA. Find out which Consulate's jurisdiction your state comes under, by going to their site. You will have to fill up the "Application for Miscellaneous Services" to get your PCC. This form is available at their site. But call them about the requirements.
Regarding Singapore, you have to get in touch with Singapore Embassy in USA. Call them up, explain your requirement, and why you need PCC. Given that its a highly disciplined nation, I am sure the process of getting PCC from Singapore would be very streamlined.