"So you think that money is the root of all evil?" said Francisco d'Anconia. "Have you ever asked what is the root of money? Money is a tool of exchange, which can't exist unless there are goods produced and men able to produce them. Money is the material shape of the principle that men who wish to deal with one another must deal by trade and give value for value. Money is not the tool of the moochers, who claim your product by tears, or of the looters, who take it from you by force. Money is made possible only by the men who produce. Is this what you consider evil?
"When you accept money in payment for your effort, you do so only on the conviction that you will exchange it for the product of the effort of others. It is not the moochers or the looters who give value to money. Not an ocean of tears not all the guns in the world can transform those pieces of paper in your wallet into the bread you will need to survive tomorrow. Those pieces of paper, which should have been gold, are a token of honor--your claim upon the energy of the men who produce. Your wallet is your statement of hope that somewhere in the world around you there are men who will not default on that moral principle which is the root of money, Is this what you consider evil?
"Have you ever looked for the root of production? Take a look at an electric generator and dare tell yourself that it was created by the muscular effort of unthinking brutes. Try to grow a seed of wheat without the knowledge left to you by men who had to discover it for the first time. Try to obtain your food by means of nothing but physical motions--and you'll learn that man's mind is the root of all the goods produced and of all the wealth that has ever existed on earth."
For the rest of the speech (it is very long, philosophical and extremely well-put) go to Capitalist Magazine online. Wikipedia has a good article on the book "Atlas Shrugged" and a list of the characters in the book for background to this quote.