Summing based on date criteria

hi all,

I've been trying to figure out how to do the following but without any luck so far.

I have a document (sample attached) that is used to track intro dates for products with dates across and item numbers down. Where an item is due for introduction on a certain day the engineer will enter a 1 into the corresponding item / date cell. I am then summing all the 1's up for a given date to tell me how many intros there are. The part I'm having trouble with is calculating how many intros there are within a given date range, which is generated initially by a TODAY() formula. Hope you can help!