Wikipedia's always a good place to start, though not always 100% reliable:
http://en.wikipedia.org/wiki/Japanese_mythology
This article's references could be better, but will give you a good overview... check also the links at the bottom once you've read the section on "Japanese Characters" which sums up creation of men and women but for some reason doesn't have a relevant heading.
For more in-depth reading on wikipedia, click some of the links in the text, like Kojiki, which is more of the story I think you're interested in.
http://en.wikipedia.org/wiki/Kojiki