Hi. I have been searching for hours and haven't found a solution
yet... Here's my problem:

I have a Spreadsheet that is tracking vehicle fleet oil change
information. One of the fields is tracking vehicle mileage at an oil
change. What I want to do is automatically populate the next field
with the current date if someone types in a value in the oil change
column.

For example:

A B C
1 car mileage date
2 600 12345 03/15/2005
3 601 33333 01/23/2005

When someone types mileage of 12345 into B2 (for car 600), I want C2 to
auto populate with the current date (ie, 03/15/2005) and save that
date. I would like this date stored and only updated if someone
actually modifies the mileage data. As an example, vehicle 601 last
had an oil change on 01/23/2005 at 33333 miles.

Any pointers?