People For Animals (PFA), Chandigarh is an organisation that works in a similar fashion to the RSPCA. It is located in the city of Chandigarh in North India. Volunteers basically help the team with the rescue and rehabilitation of stray/abandoned/mistreated animals. These include dogs, cats, horses, cattle and goats. PFA has a separate cow sanctuary (which I have visited and is awesome!) and horse rescue centre.
As far as I know, you can volunteer any time of the year and for as little or as much time as you want. You will have to organise your own boarding and meals, however.
For more information about PFA Chandigarh, visit the following website:
Although there is no information about volunteering on their website, I know that they definitely do take volunteers (albeit only a couple at a time). I visited them earlier in the year and they had a couple of volunteers from the States helping out. The vet in charge was very enthusiastic about the prospect of having volunteers over from Sydney uni when I mentioned it to her.
It really is a wonderful organisation with an extremely passionate and knowledgeable team. I would strongly recommend going over there. I reckon it would be a great learning experience to see how organisations like these function and stay afloat with the added problems associated with third world countries.
Anyway, if you are interested, contact PFA on firstname.lastname@example.org