This is a collection of some of my favorite resources on utilitarianism.

Light Books
Practical Ethics, Peter Singer
Animal Liberation, Peter Singer
The Life You Can Save, Peter Singer

Heavy Books
The Methods of Ethics, Henry Sidgwick
Utilitarianism, John Stuart Mill
The Principles of Morals and Legislation, Jeremy Bentham

Introductions
Consequentialism FAQ
Utilitarian FAQ
Common Criticisms of Utilitarianism

Organizations
80,000 Hours
Effective Animal Activism
GiveWell
The High Impact Network
Giving What We Can

Collections
Utilitarian Philosophers
Utilitarianism: past, present and future
Recommended Reading

Communities
Felicifia
Effective Altruists on Facebook Less Wrong

Essays and Blogs
Essays on Reducing Suffering
The Effective Altruism Blog
Reflective Disequilibrium
Everyday Utilitarian
Measuring Shadows
Philosophy, et cetera
Reducing Suffering