Currency Conversion Excel Document

I have a basic spread sheet. Column A = £, Column B = $US, C = $CAN, D = $AU, E = $NZ, F= €, G = Jap Yen. I regularly want to add a column of data in a currency ( say £ ) and want that data converted to the currencies listed. So all the cells in columns A to G are filled. However the next time I might have $US data that needs converting. Them all I have to do is copy and paste my required data into other Excel documents. Maybe some script to lookup the currency conversions on yahoo?