I found this cool presentation by Keith Goodnight: Kin Selection and Inclusive Fitness.

It begins with the problem of altruism, examines group selection (and rejects it), makes the key distinction between genes and organisms (replicators and vehicles), examines the greenbeard effect, explains Hamilton's rule (conditions under which gene for altruism will be favored by selection), and finally ends up with inclusive fitness:

"An individual's fitness is not based only on its own reproduction but also on all the effects it has on other individuals, weighted by their relatedness to it."

If you're at all interested in these things, check it out!