Outlook does not use an address book.
All Outlook data resides in one file. The file you need to transfer is your
Personal Folders file (*.pst) It's where all the mail, calendar, contacts
etc are stored.
Take a look at these pages for info on Outlook data backup:
http://www.slipstick.com/config/backup.htm
http://www.howto-outlook.com/Howto/backupandrestore.htm

Signature
Russ Valentine
[MVP-Outlook]
>I have a contacts address book on one computer and want to copy it to
> another computer. They are not networked. Both are XP systems. Is
> there a file/folder holding the contacts that I can copy to disk or
> e-mail as an attachment then "import" on the second machine. If so
> what is the default name of the file and default file location?