Money exchange rate in Tokyo

I'm leaving for my 2 week holiday in Japan this week. I'm trying to figure out the best way to organise money. What are the exchange rates like in Tokyo? Would I be better off changing money in Australia, changing money in Japan or just drawing money out using the ATMs? Are the exchange rates decent using the ATMs?

I heard that the exchange rates are Narita airport are really bad. Is this true? And is it any better in Tokyo post offices?

Just as a guide, I changed Australian dollars for Japan yen in a Melbourne money exchanger on the weekend for AUS$1 for 94 Japanese yen.

you need to check with your bank and see if they have any extra fees for using ATMs outside of your country.(all banks are different)It will help you decide if you want to use it or not. You can check what the exchange rate is on the internet to see if you got a good rate on the money you already exchanged. Normally the rates at the airport are not very good. I normally use the ATMs at the post offices.(at my bank I'm only charged about $3 for withdrawing 50,000 yen) or you can exchange money at the larger post offices and get a good rate. I have not used other bank ATM machines, I know I get a good rate at post office and they are always easy to find.