Shadowrun - Dodge the Rain
Great place to discover the Shadowrun setting or to learn more about all sorts of general information.
For those that want a crash course, or who simply have the attention span of a gnat:
Former North America.
An extensive timeline and history of the Shadowrun setting.
In order to destroy your enemy, you must know your enemy.
Walk like a Shadowrunner, now talk like one.
Rules for character creation, and a list of house rulings.