As the other attorneys have stated, given that you are a U.S. citizen, you want to marry him in the U.S. and he is in India, the Fiance Visa route would be the best option. This is a two stage process - first, you have to file Form I-129F with USCIS; second, if the I-129F is approved, your fiance will need to apply for his K-1 visa at a U.S. Consulate in India.
An overview of this process can be found on my website at: http://www.familytousa.com/fiance-petition-k-1-visa/
However, before you file any paperwork, I would recommend you speak to an experienced immigration attorney to ensure that your fiance does not have any past issues that would cause problems with the issuance of a K-1 visa. The attorney could also address any questions you have regarding timing, processing times and address any questions/concerns you may have.
Nisha V. Fontaine, Esq.
Serotte Reich Wilson, LLP
The K1 Visa is normally how this is done.
212 537 4407
Legal disclaimer: The statement above is general in nature, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship.