These are the Canadian Dollar to US Dollar Exchange rates (noon time), day by day for July 2009.

The source of this data is the Bank of Canada (equivalent to the US Federal Reserve Bank).

The average rate, highest rate and lowest rate for the month of July 2009 are at the bottom of the page. 

You can use these rates to compare to the rate your credit card offers or other foreign currency transactions.

These are actual market rates, so don't expect to get these yourself. Since the currency exchange markets are closed on weekends/holidays, there are no rates for these dates, but trading is usually pretty thin on these days, so using the closest day's data is usually a valid approximation. 

Helpful Articles for US$ Banking for Canadians

If you often transact in both Canadian and US Dollars, take a look at opening up a bank account in the USA, which will give you a Visa or Mastercard ChequeCard (ie: a Debit Card that works through the credit card system). Or open a US$ Account at a Canadian bank. Look at the MBNA Smart Cash Credit card to get 1% or more back on almost all of your purchases, which can cut currency exchange commissions significantly. 

Day-by-Day US Dollar to Canadian Dollar Exchange Rates

Throughout the month, the US Dollar was worth more than the Canadian dollar, so be careful of your calculations to ensure your calculations are correct. In other words, everything should cost more in Canadian Dollars and less when denominated in US Dollars.