Twitter Facebook Google Plus Linked in

Backing up Microsoft Outlook .pst files

Instructions for backing up Outlook files, with extension .pst

Microsoft Support has 3 excellent articles that address this issue directly.

How to manage personal folders files in Outlook

How to automatically back up your personal folders file in Outlook 2000 and Outlook 2003

How to manage .pst files in Outlook 2007, in Outlook 2003, and in Outlook 2002