Using Cell Values as Equation Variable

How can I use cell values in an equation?

For example in one cell is the number 1 and the next cell is the number 10. Let's assume this input means I want to get the sum of all cells in column A from row 1 to 10.

How can I create a formula that is able to form an equivalent of "SUM($A1:$A10)" by using the 1 and 10 values found int he sheet. If, instead the values were 5 and 50, I would be looking for "SUM($A5:$A50)".

Anybody have any insights on whether or not this is possible in Excel 2003? I know how to reference other cells, but not how to use those values in formulas.

Thanks.

See Excel's help files for the INDIRECT function and see if that's what you need.