Posted here every day. The file you need 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 or transfer:
http://www.slipstick.com/config/backup.htm
http://www.howto-outlook.com/Howto/backupandrestore.htm
http://office.microsoft.com/en-us/assistance/HA010771141033.aspx

Signature
Russ Valentine
[MVP-Outlook]
> Daughter gave me her computer which has Outlook 2003 on it, but it was
> never used. I use Outlook 2000 on my old computer.
>
> How do I transfer the outlook 2000 data file from the old computer to the
> new computer? Is the data file structure compatible?