When we were there last March, the Citibank machine was broken. There were an American Express machine and 3 or 4 Japanese Banks ATMs. There was a que for the AMEX machine so we decided to try the Japanese banks. We took 60,000 Yens from a Japanese Bank's ATM with our BankofAmerica debit card without any problem.

Remember, there are 2 different types of ATMs in Japan. Only the ATMs operated by Citi and Post Office joint venture accept foreign cards. They do not work 24 hours either. All the ATMs at NRT accept foreign cards. In town, most Citi's work 24 hours. Post Office ATMs close at 5pm. So it would be advisable to make large withdrawal at NRT so you dont have to worry about it for the first few days.

You can do a search at the Travel / Asia forum for ATM info.

If you walk from Park Tokyo to Shinjuku, you will pass a Citi ATM about midway on the same side of the road.

Also you can search Visa or Mastercard ATM locations in Tokyo.