I too would recommend to look into André's book very much, and several articles by Deligne, esp. "Hodge I", "Valeurs de fonctions de L et Périods Integrales", "A quoi servent les motifs?". I found <a href="http://people.math.jussieu.fr/~nekovar/lect/motives.pdf" title="Nekovar's slides">Nekovar's slides</a> and Barbieri-Viale's <a href="http://de.arxiv.org/abs/math/0508147" title="motivic Pamphlet">"Pamphlet"</a> usefull too.  

Edit: Goncalo Tabuada held a talk on "the construction of the categories of noncommutative motives (pure and mixed) in the spirit of Drinfeld Kontsevich's noncommutative algebraic geometry program. In the process, I will present the first conceptual characterization of Quillen's higher K-theory since Quillen's foundational work in the 70's" (<a href="http://www.mpim-bonn.mpg.de/node/3501" title="link">link</a>). It would be interesting to know where one could read more about that.