from outlook express help files
--also check aol email help files------------
To import an address book from another program
You can import address book contacts from other Windows
Address Book files (.wab), as well as from Netscape
Communicator, Microsoft Exchange Personal Address Book,
or any text (.csv) file.
For Windows Address Book files:
In Address Book, on the File menu, point to Import, and
then click Address Book (WAB).
Locate and select the address book you want to import,
and then click Open.
For all other address book formats:
In the Address Book, on the File menu, point to Import,
and then click Other Address Book.
Click the address book or file type you want to import,
and then click Import.
If your address book is not listed, you can export it to
either a text (.csv) file or an LDIF (LDAP Directory
Interchange Format) file, and then import it using that
file type.