The one on www.equitymaster.com is pretty good / convenient. It is free for the first three months.
If you get an ICICI Direct.com trading account (750 bucks per year), it comes with an automatic Portfolio management software, where after market hours one just clicks a button in the Trade Book and the portfolio gets updated. Very convenient indeed.
Best is to use one of these online programmes and maintain one's own Portfolio in an Excel file separately , just for offline verification. MS Excel is a very handy and versatile programme for maintaining a portfolio.
Rgds,
Uday.