you have asked many questions ... startup scene is not bad in india - the VC fundings are also available there ... apart from that you need to decide by yourself whether you can commit time and energy that can add value to your friend's dream. also if you are in US then you can also take advantage of all the startup programs and apply for it to see whether you can get launching pad. you may also explore about incorporating your company in USA to leverage benefits (if any). Also communication with your partners will be the key ... all 3 of you will be required to be on the same page as far as vision of your product/service is concerned. Lots of time will be invested in tele-conference, also make sure how you are going to get your partner equity, keep everything on paper and legal so that you dont face any problem in the future.

EDIT: it also depends what role you're going to play from here, will you be a main hacker? if yes, then you will be busy in communicating to your partners - if you are going to handle online sales, marketing and PR from here then it could be easy and fast due to broadband connection and other infrastructure.

All the Best !!!