So many issues but where to start ...
I'm of the female persuasion and I work in technology. There I said it and I didn't even cringe. I don't have a technical job, but I do have a serious inner geek that likes me to read sites like this one, watch science programmes, and actually coo over new shiny kit. I can hold relatively technical conversations with our IT teams and scare the pants off our support desk because I don't fit into their script. I know that I'm respected for my knowledge and that I show an interest even when it isn't broken!
You can blame the IT Crowd for many things (painfully unfunny and too many reminders of places I've worked, IMHO of course) but not for why girls avoid IT careers. There is a definite issue with the way its taught in schools even if you ignore the curriculum. You need to inspire them to do something creative not bore the poor sods to death for a start. As has been pointed out, IT is a huge subject with many specialisations its not just wires and programming.
There is also a huge problem now with the rise of the smartphones/tablets era. So much of how to make it work is now completely hidden from the user to even start to become interested. Its the same with Windows and OSX to an extent. You switch them on and use an app. No clue on what the hardware does or how the apps interact with the OS, let alone how to fix them when they have their "moments". All the interesting bits are now hidden away or locked down and its not so easy to poke them just to find out what its doing.
I think one of the biggest problems of all though is actually the media. Its wall to wall celebrities (and I use that term loosely) with a definite lean towards those that using their looks for all they are worth. Those with a brain barely get a look in and if they do usually end up with the moniker "thinking man's crumpet" attached to them - yes it is the exactly the same for the men too particularly if they are relatively easy on the eye. Its all bloody WAGs or becoming famous without having done anything (preferably rich too but that seems optional).
If all the role models are people like Colleen Rooney or nobodies from Big Brother, then what bloody chance do we have?