Why do you want to get into IT?
If it's for the money, then you might be wasting your time. If it's because you love tinkering with computers, you *might* get lucky and the money will follow later on.
Get yourself a linux box and use it to learn scripting, admin and programming (Python, Ruby).
Go onto the Khan Academy and Code Academy sites and run through some of the tutorials.
If you are serious about networking, sign up with the Open University and learn all the skills you would need for a CCNA. This will cost you, but you'll get a lot of hand holding / tutorials and at the end of it you should be ready to take the CCNA exam.
Get a Raspberry Pi, and get it to do something interesting.
Pick an area that interests you personally. Is it's media players, then install XMBC and Navi-X. If it's programming then learn a bit of Perl and install ImageMagic module and get it to, I dunno, make thumbnails out of hundreds of your photos. Hang around on internet forums and ask loads of questions (after you've searched carefully for the answer already of course!)
You'll get none of this from studying for a qualification, and most companies are looking for experience and a can-do attitude.
About your idea of starting with a help desk, I think that's risky as most help desks these days seem to be just about logging calls with very little chance of career progression.
Good luck! I've been doing IT for 20+ years and I still love it. :-) (actually 30 if you count BASIC programming on the Vic 20)
Biting the hand that feeds IT
