Traditionally, Indian Peafowl are considered monotypic but have a host of mutations.
There is, however, some regional variation between the Indian Peafowl, especially the birds of Sri Lanka are quite distinct from the mainland birds.
With the current status of Indian Peafowl in captivity, nobody is clear about its status in captivity.
The nominate Indian Peafowl is found throughout much of India except the south. The front edge of the wing is laced not barred:
http://www.flickr.com/photos/mridulbatra/2438629676/
http://www.flickr.com/photos/kalsnchats/4475531118/
The Indian Peafowl has several races, not genetically distinct to be considered subspecies. In Shimla and Rajasthan, along the foothills of the Himalayas, we find one distinctive geographic variation:
This is the more stocky-built, chubbier Nepalese Peafowl, P. cristatus var. nepalensis. It is designed to live in higher elevations and has a thicker and more insulated plumage. It's crown is especially thick and shiny. The females of this form look almost like a spaulding.
It is possible that Indian Peafowl were never native to southern India. These birds appear have been introduced from Sri Lanka, the subspecies is Pavo cristatus singhalensis:
http://www.flickr.com/photos/51405727@N00/5399074198/lightbox/
You can see in that last link, the crest shape and bold facial skin of this bird. The wings are barred differently and white not toned with yellow. The female has a greener neck:
