Visas For Travel to India
For US citizens, besides needing a passport, please know you are required to apply for and receive your official Indian Tourist Visa while in the USA, before you go. You’ll have to submit your passport to the visa outsourcing firm (link below) along with the payment/fee they require. In 2012, the 6 month Visa fee with processing included, is about $76 per person.
The State Department has a good overview of Visa requirements:
U.S. and Canadian citizens can use Travisa, a fast and easy way to help speed up the process of obtaining your passport and visa.