Y: The Last Man publisher Vertigo Comics has a PDF of issue #1 that is available for free. This is the perfect refresher for fans as the final issue (#60) comes out this month. Also, as the movie adaptation gears up you can find all the issues of Y: The Last Man at the Comic Book DB. They describe each issue and how to find yourself a copy.
About Y: The Last Man
Written by Brian K. Vaughan; Art by Pia Guerra and José Marzá, Jr.; Painted Cover by J.G. Jones
When a plague of unknown origin instantly kills every mammal with a Y chromosome, unemployed and unmotivated slacker Yorick Brown suddenly discovers that he is the only male left in a world inhabited solely by women. Accompanied by his mischievous monkey and the mysterious Agent 355, Yorick embarks on a transcontinental journey to find his girlfriend and discover why he is the last man on Earth. But with a gang of feminist extremists and the leader of the Israel Defense Forces hunting him, Yorick's future, as well as that of the human race, may be short-lived.