I am looking for a website that has historical financial information
(profit & loss statement/also known as income statement). This website
will have this historical financial statements for companies that are
public on either of India's stock exchanges (NSE, BSE). Indian laws
require companies that go public to release the four most recent years
of financial information while the company was private. I'm very sure
this information is online, I can't seem to find out where.
to find that information.

Dear Ramdabom

            I searched for you, i got one informative site for indian
companyies income statements and shares details in
http://www.indiainfoline.com/. I hope this site enough for your
requirment. In this site the following links will guide you.

STOCK MARKETS 
COMPANIES 

  Click COMPANIES link and search comapany name ( just enter first
letter of the company this list the company). Select the company and
see the history and under Financial Data view Profit & Loss,Balance
Sheet,Cash Flow,Ratio Analysis.

Thanks for your help!

This link doesn't have historical data for the 2-4 years preceeding
the IPO when the company was private. These files are probably in some
online Indian government database somewhere, not unlike the SECs
website in the US.

There are no restrictions in India for startups to go for IPO like in
USA. Greenfield projects with out performance also can go for listing
in India. So the data you are looking for has no significance in
Indian regulatory agencies perspective or Merchant banks perspective.

http://www.bseindia.com/qresann/searchresult.asp?scripcd=509704
http://www.nseindia.com/

BSE and NSE carry annual and quarterly results. Please let me know if
this answer fulfills what you are looking for.