I've a spreadsheet with thousands of rows of people (last name, first
name, address, etc.)
I need to weed out duplicates, and sorting by lastname, firstname and
then scanning the firstnames for duplicates that have the same last
name is onerous!!

Is there a way to have Excel (2003) show only rows in which there are
more than one of a given value in a column?
So let's say there's only one row with a value of "Jones" in the
lastname, it'll now show that row but it'll show the three rows with
"Smith" in the column?

(Would be really cool if it showed rows in which there are more than
one with the same value in TWO columns, but I won't dream that big.)

Thanks for any suggestions!
Liam