Just read a guide on this subject from mungo115....
I'd like to put an opposing view. I live in New Zealand and often buy from UK and US sellers and I have had no problems - see my feedback! If the item is a CD or a DVD, then we have to pay a lot of postage to get the item to NZ, but there is no issue from the sellers point of view - all thay have to do is stick more stamps on the item. I accept that for large items there is a much greater problem, but if your item is small, please consider your colonial cousins and only stop bidding from outside the UK or US if the item is 'bulky'.