the following quote is from Aladin:
"The method is as follows:
Enter in some column what follows:
{"USA";"FRANCE"}[ That's, enter USA in a cell, then FRANCE in the next cell down ]
Select these cells, go to the Name Box on the Formula Bar, and type COUNTRIES followed by enter.
Enter in a column next to COUNTRIES:
{"New York";"Pittsburgh";"Los Angeles";"Boston"}
Name this range of cells USA via the Name Box as described above.
Enter in a column next to USA:
{"Paris";"Nice";"Toulon"}
Name this range FRANCE.
Just to see how this works,
activate A1 in some worksheet in the same workbook;
activate Data|Validation;
choose 'List' for 'Allow';
enter as 'Source' the formula:
=COUNTRIES
click OK;
activate another cell in the same worksheet, say, C1;
activate Data|Validation;
choose 'List' for 'Allow';
enter as 'Source' the formula:
=INDIRECT(A1)
click OK.
Now you have two lists of which the 2nd depends on the selection from the 1st. "