Rules and Variants.
Official Rules[]
The offficial Rio Grande Games rules can be found here:
Base Game: http://www.riograndegames.com/uploads/Game/Game_278_gameRules.pdf
Intrigue: http://www.riograndegames.com//uploads/Game/Game_306_gameRules.pdf
Seaside: http://riograndegames.com/uploads/Game/Game_326_gameRules.pdf
FAQ[]
The BoardGameGeek FAQ for Dominion can be found here: http://www.boardgamegeek.com/wiki/page/Dominion_FAQ
Variants[]
The Wikia page on Variants can be found here: