Found this:
Your Windows Address Book
Find Your Windows Address Book
-Click Start, and then click Search.
-Click All files and folders.
-In the What do you want to search for box, click All
files and folders.
-In the All or part of the file name type, *.wab, and then
click Search.
-When the search is finished, double-click each file to
open it. When you have found the correct one (it will
contain your Contact information), note the exact
location and name of the file.
Import Your Windows Address Book
-In Outlook Express, click the File menu.
-Click Import, and then click Address Book.
-Point the Look In field to the location that you noted in
step #5 of the "Find Your Windows Address Book" section.
-Click the .wab file, and then click Open.
-Click OK to import the Address Book.