The League for Programming Freedom has two position papers, "Against User Interface Copyright" and "Against Software Patents," and other information.
Norm's figures about illegally copied software are taken from Tom Forester and Perry Morrison, Computer Ethics, MIT Press, second edition, 1994, p. 52.
The classical source for Kant's ethical theory is his Foundations of the Metaphysics of Morals, also translated with a variety of other titles. It is a very small book, but not easy reading. Kant's Lectures on Ethics (Harper Torchbacks, 1963) is a more readable introduction to his ethical thought; it is a reconstruction of his lectures based on notes taken by three students.
John Stuart Mill's Utilitarianism is an excellent introduction to utilitarian ethics.
Aristotle's major ethical work was the Nicomachean Ethics. Plato wrote many dialogs on ethical problems; one of the most famous and systematic, from the point of view of relating moral values to human nature, is the Republic.
Other references:
Barrett, Lee E. (1989). Untitled paper on the patentability of mathematical algorithms and computer programs.
Davis, Randall, Pamela Samuelson, Mitchell Kapor, and Jerome Reichman (1996). "A New View of Intellectual Property and Software," Communications of the ACM, vol. 39, no. 3, March 1996, pp. 21-30.
Diamond v. Diehr, 450 U.S. 175 (1981).
Hobbes, Thomas (1651). Leviathan.
Johnson, Deborah G. (1985). Computer Ethics, Prentice-Hall.