That's
today. I wrote a three part series on the gender gap in wages three years ago, and it's still pretty much readable. Highly recommended, because usually I'd charge for all this information, and here you can get it for nothing! Whatta bargain! Also probably one of the reasons women earn less. Heh.
The story is actually fairly complicated. The theories about the gender gap are discussed in
Part I of the series and the empirical evidence in
Part II.
Part III answers the usual wingnut counter-arguments and shows why they are wrong.
Enjoy.