Microsoft Outlook XP 2002 or 2003 user? There's a program called Outsource-XP which is great to backup all of your Outlook information. It backs up your emails, settings, email accounts, templates, address book, etc. - just about everything you would use Outlook for! It's a really cool program if you are switching computers, reformatting, or just want to keep backups on hand. I use it and recommend it. It's made by TotalIdea and available from http://www.totalidea.com/frameset-outsource.htm for about $25.
Another similar program is called the Outlook Express Backup Genie and is available at http://www.amicutilities.com/outlook-express-backup/ for $30. I've never tried this program but it looks promising. As opposed to Outsource-XP, this proggie backs up mail from a variety of email clients, not just Outlook. Plus, it includes an automatic scheduler so you never miss a backup. However, unlike Outsource-XP, only mail is backed up.