In a 2008 survey of the American blogsphere, women were equally represented among blog readers, and broadly equally represented among blog creators.
If you're looking for women bloggers, you'll find many gathered together at Blogher (which holds annual conferences), and through blog carnivals such as the Carnival of Feminists, and Scientiae, for women in science, engineering, technology and math.
Women of varying interests also gather together in cyberspace, from gamers, to women of faith, from supporters of women's sport to supporters of women in politics, from women in development workers to supporters of women craft workers.