There is the Connaught Palace stretch in Delhi, the whole lane leading up to Churchgate in Mumbai, also friends tell me of similar places in Kolkatta and B'lore, where most of the popular tech books' pirated versions are available pretty cheap. Now, I am not endorsing privacy, but if you are actually so desperate..

Also, indiaplaza.in has some deal with some international book publishers, they take good 30 days to deliver such "international books" but they can be bought in India.