cmeagan656, that's not correct if the user is using Outlook 2003 in an Exchange environment using the default settings.
marcasii, you're cross posting this in various areas, and shouldn't.
If you're using Exchange 2003 and Outlook 2003, the .ost file should be in
\Documents and Settings\<USERNAME>\Local Settings\Application Data\Microsoft\Outlook
If you're not using that combination, you could look for a .pst file ANY place that the user had WRITE access to, including the local workstation, ANY/EVERY server, AND/EVERY workstation with an open share, etc.
Past that, you're going to need to look to your backup solution, which should provide you with a full copy of the mailbox.
Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)