You could have an event macro that looks for a change to values in a certain
column and then sorts the data.
But I wouldn't do this. If you make a typing mistake, it could be difficult to
find where that row with the error moved.
Instead, If you're using xl2003 (or higher), you can apply
data|filter|autofilter. There's an option under each arrow that allows you to
sort the filtered range by that field.
If you're using any version of excel, you can use a technique at Debra
Dalgleish's site:
http://contextures.com/xlSort02.html
If you're new to macros:
Debra Dalgleish has some notes how to implement macros here:
http://www.contextures.com/xlvba01.html
David McRitchie has an intro to macros:
http://www.mvps.org/dmcritchie/excel/getstarted.htm
Ron de Bruin's intro to macros:
http://www.rondebruin.nl/code.htm
(General, Regular and Standard modules all describe the same thing.)