I am writing an application (for personal use) in Visual basic which uses yahoo's Stock Quote API in visual basic (i.e. http://download.finance.yahoo.com/d/quotes.csv) for fetching the stock. According to yahoo it provides real time data for the NATIONAL STOCK EXCHANGE OF INDIA(NSE) for the users who have logged in. Others get a 15 minutes delayed quote.
Please let me know the means to do the yahoo authentication.