It was brought to my attention that perhaps there is some confusion on the idea of psychometric g . I wrote a brief article about it in a student newsletter a few months ago, that does a brief explaination. My stuff starts on p. 11.
For more in depth, I suggest reading:
Jensen, A. (1998). The g factor.
Carroll, J. B. (1993). Human Cognitive Abilities.
Deary, I. (2000). Looking down on human intelligence.