Around 38 percent of Indian Internet users (14 million) spent an average of 8 hours per week online ,as found in the last CNET survey . Due to the same reason,we see a proliferation of sites providing books in Electronic form (E-Book) .
I have used the below sites and feel they have a decent collection of books on varied subjects and might interest people from varied backgrounds ( though it might appeal more to people from computer science background ).
Some of the links are :
There may be more and better sites . If anyone comes across , I would be happy if you too let me know about them.