Yes I know the answer!!! I asked this question on another site recently. Marmite is sold in some supermarkets like Coles and Safeway, but alot of people say, including my sister, that it doesn't taste the same. There are a couple of places in Melbourne and Sydney
www.treatsfromhome.com.au/category21_1.htm
Saying that I posted her a 250g jar yesterday and it cost me over £5 to send. She can buy her own jar next time!
Good luck