This will probably seem a bit confusing but here we go anyway.

I have a sheet that is populated each day. I want to present the sum of the column, but I want it to be based on the last column with data on it.
Every day new data is automatically entered into Column B. I need to sum the column but I need it from the previous day. From the example below I would need the sum of B1 thru B:4. I can do that but I want it to be mobile. I want it to automatically give me the sum of B1:b5 tomorrow.
I am doing this because I am tracking "today's" number and "yesterday's" number. I was trying to do it using vlookup and offset to set the starting point based on the date. But I am unsure how.
A B
1 8/20/08 9
2 8/21/08 20
3 8/22/08 16
4 8/23/08 9
5 8/24/08 11
6 8/25/08
7 8/26/08