Sumproduct on Dates?

I have a column of dates (in calendar order3/1/08, 3/2/08, 3/3/08,etc...) and
a column of corresponding $ amounts next to each date. I need to be able to
enter a date in a cell and enter a number of days for instance "5" in another
cell and in a third cell return the sum of $ amount associated with the 5
days starting with the date entered.

Thanks in advance