We are currently developing multi-language online shopping site and would like to setup prices and accept payments in different currencies. The point is that all major payment processor require only $US parameter to be submitted when processing the order. So that the only way we can see now to solve the problem is to implement a currency converter into website. But it would be nice to find a good payment processor to accept different currencies. Do you have any ideas about this?
There are several platforms that you can use for multi-currency processing, and it's a good idea if you are targeting multiple territories.
I work on these issues consistently and have an important feedback for you to keep in mind when you are setting this up -- If you are selling in multiple currencies, you may want to develop your shopping cart so there is a master currency, and an exchange rate multiplier used to calculate the other currencies.
For example, base all your pricing in USD, and then use a geo-based IP check to figure out what country the visitor is in. If you support the currency of the country they are in, use the exchange rate multiplier against the USD base currency to display the pricing for their products.
This is important because exchange rates change over time (look at the Canadian vs US dollar over the last 1.5 years) -- and your pricing will really go out of sync if you hard code your currencies. That is why I like an exchange rate multiplier. If you have a smaller catalog this may not be an issue.
I believe the main point here is to let customer know exactly how much he will pay in his currency. Most payment processors allow customers to choose the currency for the payment, however customers will be charged the amount according to the exchange rate of the processor (and usually it is not for customers' good). So customers are often charged more than they expect.
That is why to my mind it is important to show customers the final price they would pay.