India Post in its website has posted a catalog in pdf format which has the list of stamps from 1947 - 2011, It also has the list of definitive stamps. visit www.indiapost.gov.in
It has also announced date for forthcoming stamps release for the month of July 2012.
London 2012 Olympic Games - 25.07.2012.
50 Years of Customs Act,1962 - 26.07.2012.
Durga Prasad Chaudhary - 31.07.2012.