From personal experience though, ebooks are not really much good.. sure you can get them for free sometimes, but reading a whole book (especially one with technical literature) on a computer, can be very painful. I would suggest you pick up a good book from a bookstore. Since you're in India, you could check out
The CCNP course is one that requires proper studying and good material to help you. With this in mind, I'd advise you to consider grabbing a few books from Amazon.com, which will surely help you more than the ebooks.
You can firstly goto Cisco's website and check out the latest available exams for the CCNP, and then search on Amazon.com for the books offered that cover them.
P.S The CCNP requires you to have a valid CCNA, before sitting for the first exam.