Hi, I dont think we have any free services to access NSE quotes. I had the same requirements sometime ago and I implemented using the HTML parsing. There are numerous sites which displays the current price of the stock when you send the stock code as the query parameter.
Parse the return HTML (using regex) and get the price part of any exchange BSE/NSE. The only issue here is, if the site changes its display, then you may have to modify your parser also.
Ganesh