I'm an aussie too working at Perisher this year, thinking of getting some ski resort work in europe this coming winter... there are websites like
http://www.seasonworkers.com/fe/ for finding jobs but a lot of the resorts will want you to commit for a whole season. If you think you can only come in halfway, you might actuall have a pretty good chance of finding a job if you go to the resort and ask around.... i know thats how it works here, after about the first month we see ads going up everywhere for employment to replace workers have had to leave unexpectedly, been fired, quit etc. i googled ski resort employment and came up with heaps of stuff so you should be able to find something on the internet before you go