Hi,
There is an organization called the International Monetary Fund that posts exchange rates Monday through Friday. It looks like they post US Dollar based rates each weekday to this tab delimited file:
http://www.imf.org/external/np/fin/rates/rms_rep_pt.cfm
Here's an html version:
http://www.imf.org/external/np/fin/rates/rms_rep.cfm
Are you looking for bank-to-bank exchange rates or rates that you or I would get if we walked into a bank and asked how many units of a foreign currency we can purchase with our 10 units of domestic currency (which, of course, is quite often answered differently than when we ask how many units of our foreign currency we need in order to purchase 10 units of domestic currency).
A commercial lender might be better if you are looking for currency "street prices"