I don't use a Mac, but if the cell really contains those alt-enters (line
breaks), I could do this on a wintel machine:
Insert a couple of extra columns to the right of the column with the addresses.
Select the column with the addresses
data|text to columns (xl2003 menus--I don't know on xl2004)
delimited by other
I'd use ctrl-j
(or hold down the alt and hit 0010 on the number keypad)
skip (do not import) the empty fields)
and finish up.
Save your workbook first--so you can close without saving if it screws up your
data (or just use undo???).
You may want to post here:
if this suggestion doesn't work.