I am building a store for a client using freemerchant.com

They do not offer on the fly currency conversion. My client wants this. The solution I thought would be to have a small link saying 'currency convertor', with a pop up window, with some javascript which let you put in the price in pounds, and then the result in their chosen currency.

Any pointers or scripts would be appreciated, i have no javascript experience.


Thankyou
james