Actually I am in the States so I have not had to deal with this problem. Many of the companies that are cited on the web are reputable, but you would have to check each individual company to see whether they ship abroad. I can't imagine why an ibook would be difficult to ship.
PS. Apple also maintains web sites in each country and some of these sites sell refurbished Apple equipment (with full Apple warranty) for a reduced rate. The UK web site offers this equipment each Wednesday. You might want to check out the Aussie Apple web site, perhaps they do this as well. Just to let you know I bought my Apple Titanium as a refurbished model for about the same as I would have paid for a new ibook (and it was a G4 not a G3), and it has been wonderful - no regrets.
Todd