Take a look at http://www.4-consulting.com/News/Ezi...e_4_03.htm#t16

"John M" <John M@discussions.microsoft.com> wrote in message
news:D9291E32-66A0-4258-96D6-22EDBE3E6B28@microsoft.com...
> I am looking to entering a value into column A (Data Point), then on
column B
> (Time Stamp), the time that value A was entered. Then another value will
be
> entered into A2 and would like the time that Data Point 2 was entered into
B2
> and so on. I have tried the IF statement =IF(A1,NOW(),"") in B1,B2, B3...
> but every time the work sheet reculculates, the Time Stamp column becomes
the
> same. How can I stop this from happening or am I going about this the
wrong
> way.