I'm the other way around, in IT considering changing to aviation.
First up, if you are doing any sort of IT role in the company, try and make it somewhat official, ie don't just be the guy everyone comes to in order to fix things, get it in the job description/cv that you were the xyz... for the company. It might even advance to them providing some basic courses? Either way it would be a great bonus on the cv when looking for a job.
IT can be like aviation (I guess), plenty of courses to take you from zero to hero, but how good can you do the job?
I'd say stick to industry certification / training, ie a technology or product field, grads come out of 3 years university, computer science, information technology whatever, but often are of no use to an IT department because they can't do anything, if their lucky they might have enough practical knowledge and plain english to work on a helpdesk.
Get into Microsoft or Cisco qualifications and you're dime a dozen, but then again just about every company use these companies, well at least microsoft.
KNowing the Office suite is worth something as often your only break into the industry might be on a helpdesk. If you want to do the physical stuff, ie fix build hardware, then it's different, but then there's a limit to how far you can go. As it is a lot of 2nd/3rd line systems engineers will often build their own servers anyway (depends on the size of the company), kit like compaq is so standardised and designed as modular these days that it's dead simple. I wouldn't recommend going into hardware.
On the plus side, I find it's not just what you know, but how you can apply it. You can easily find guru's or pay for somebody to gain the knowledge. But it's damn hard to find people who are "good". If you want to get into developing then if you are methodical and have an eye for detail then that;s a great skill, I get sick and tired of sloppy developers who leave all sorts of inconsistancies in the product, leave out the most basic things such as error trapping. On the support side if you can problem solve effectively you will be a great asset. time and again you can get guys with all the know how but they are only good for design and set up, put a crashed system in front of them and they can stuff around with it all day never getting anywhere.
I think I'll stop there for the moment, just realised it's midnight and I think all I'm doing is waffling, I'm not sure I've actually made sense
Cheers