A great graphical tool is Yahoo finance- As a test case I took the Indian Outsourcing and IT industry and compared their stock performance for the whole of 2008.
Business case- As you can see, the Indian IT sector lost tremendous value in 2008 , perhaps too much so you can see the sharp pullbacks in the last one week ( WNS pulled almost 18 % up). One view I belive this industry will do well to adopt is stop being an Information Technology Enabled Services (ITES) and start moving towards Information Technology Enabled Products ( ITEP)
Updated- I didnt factor in Satyam’s acounting scandal in the analysis.If you click the link above now – you would note the impact such events have on domains ( and curiously happen again and again.It also leads to better data mining solutions than simplistic history repeats itself models).
Yahoo finance is extremely user friendly and the design of the interface is sweet,short and simple. But the biggest weakness is ( and it seems like a Yahoo weakness) – there are almost no ads compared to Google Finance which focuses on the ad placement and relevancy over anything else. I hope this site endures ..as it is a great boon for analysts and even stock market researchers.