It depends on the job
I don't know what would encourage more women to go into IT. I think many of them are just not interested. I'm a female Network Admin and have been for over 25 years. In my particular job, I have worked with very few women in my capacity over the years and I think its because of the demanding nature of the job. Many women have families to care for and that takes precedence over a job.
I have seen women in other less demanding IT jobs though, so I don't think its a problem that companies and schools are not doing enough to encourage women. I think it depends on what IT job you're talking about. Supporting the infrastructure of a company might not be attractive to most women because of family obligations, but programming or training might because it offers flexibility. I've been everything from a help desk person to an IT Director and don't think I've ever been denied any job because of my gender. Yes, in my capacity, I work with mostly men. Thats ok, I like working with men and have no problem fitting in and being one of the "guys".
AV
