Hm, I don't recall that being the case for me. I've used my bank card and my visa/amex cards overseas and I don't believe I've ever been charged a fee on top of the currency exchange rate. I've always presumed the fees are folded into the exchange rate itself, which is still better than what I get at most over-the-counter places here and sometimes even better than bank exchange rates.If you buy in a different currency to your card you have to pay an extra fee.
Perhaps it's a country-by-country difference?
In any case, I've got more and more clients now using the eCheck method as their way of paying us through PayPal. It withdraws directly from the client's checking account, and I presume PayPal does the exchange, so there shouldn't be any banking fees, but I'm not sure about that. Either way, I love eChecks now because I get charged E5 rather than a percent commission!