There have definitely been increases in girls entering non-traditional and technological fields. There's a wonderful organization called Actua. They have a girls program focused entirely on science and technology. They're part of the Girls Action Network and they do very good work, especially around math, science, and technologies.
It's part of the role modelling thing. We have Roberta Bondar, but there aren't very many more we can think of, women who have succeeded in technological fields. Maybe we need to shine more light on who is there, as well as create girl-specific spaces within schools, within community centres, where they can discover their interests. If girls are seen as being interested in that, they don't get a lot of support.