How can I add NASDAQ and the S&P 500 to the iPhone stocks widget?

Several users have asked both here at iPhoneFAQ and on a variety of discussion forums how to add NASDAQ and the S&P 500 indexes to their iPhone's stock widget. The Dow Jones Industrial average is included on the iPhone by default using the symbol ^DJI.

You can add the NASDAQ and S&P 500 using the following symbols:

NASDAQ: ^IXIC
S&P 500: ^GSPC

Thanks to b_behringer, an Apple Discussion Forums user, for the answer.