In all reality, one of the best places to start is Wikipedia. The sources quoted in the game theory articles are fantastic.

Also, "Game Theory" by Fudenberg and Tirole of you're mathy, or Gibbons if you're wanting a fairly awesome introduction: http://www.amazon.com/Game-Theory-Applied-Economists-ebook/d...

There are also a lot of blogs on algorithmic (computational) game theory if that is of interest to you.