Or on the same page as Winterwolf's advice, if possible, setup a different US bank account that doesn't charge you a transaction fee for using foreign ATMs. I've used this example before but I had IndyMac Bank until last summer (when it unfortunately went BOOM) but I never had any transaction fees charged for any ATM usage whether it was at the post office or 7-11 ATMs. It was a really great service and convenient because their exchange rate was usually just the rate set by the market the day before (with no extra fees taken off). I'm sure there are other banks that offer a similar service.
Of course, in this day and age, it probably isn't the best idea to deposit all of your salary in there but I'm sure your company will allow you to just deposit a certain percentage of your salary every month to different accounts...