Hi Damien
Australia is a good place to come to for IT work as there's loads of it and probably less competition that the UK.
However, we are flooded by highly educated graduates with no commercial experience, therefore, I would recommend talking to one of the global consulting companies (KPMG, Accenture, Deloitte, E&Y etc) in the UK and see what they say about your chances with them. They might even sponsor you but be prepared for long hours and hard work.
www.seek.com.au is the most commonly used site for advertising IT jobs, but worth checking the individual companies websites too. What stream of IT are you focusing on?
You really do need to do some research yourself as each case is individual. However, Australian unemployment is very very low and the cost of living isn't bad either so worth checking out.
Pj