You can use the INDIRECT function: ="B" & A1

There are other examples he

http://www.contextures.com/xlFunctions05.html

wrote:
Hi,


Let's say I have a worksheet with a value at cell A1, and I want to use
that value as an index into another cell in column B. So if A1 has the
value of 2, I want to be able to pick up that value and get the cell
location for a formula (in this case it would be B2). How would I do
this?

I checked the Index function, but it doesn't do what I want. I tried a
direct approach of juxtaposition, but to no avail.

Any help would be greatly appreciated.



--
Debra Dalgleish
Contextures
http://www.contextures.com/tiptech.html