this is easy enough, here's what you do:
say for example that on each spreadsheet file, your beginning balances for the month are in row 1, and your ending balances for the month are in row 30. now let's say that you have two files, january.xls and february.xls. to get the ending balances for january.xls cell A33 to appear in the february.xls file as the beginning balance in cell A1, you would follow this procedure:
1. open both files in excel
2. go to february.xls, cell A1
3. click the equal sign (=), then go to january.xls, row 33, select it, and press the enter key.
4. you would notice that a formula has appeared in cell A1 in february.xls, which is a link between the two files, that contains a cell reference to january.xls, cell 33.
just follow this procedure for all of the other cells you want to link (just change the names to fit your circumstance), or once you are familiar with the formula to establish the link, you can just type it in. good luck!
kevin