You need to back up one or more mailboxes without backing up the databases that contain them.
Download the ExMerge utility from the Exchange Server 2003 tools page (http://www.microsoft.com/exchange/downloads/2003.asp). You can use this version of ExMerge with any version of Exchange, but you must run it on an Exchange Server 2003 server or a machine with the Exchange Server 2003 version of ESM installed. Install it according to the directions in the Mailbox Merge Wizard (ExMerge) documentation.
Launch ExMerge. At the welcome screen, click Next.
Select the Extract or Import (Two Step Procedure) radio button on the Procedure Selection page and click Next.
On the Two Step Procedure page, make sure the Step 1: Extract data from an Exchange Server Mailbox radio button is selected and click Next.
On the Source Server page, supply the name of the Exchange server where the mailbox is housed. You can optionally specify a DC and port number to use when looking up the account of the user whose mailbox you're backing up; doing so speeds up name resolution somewhat.
Click the Options button; this displays the Data Selection Criteria dialog box.
On the Data tab, make sure that all of the checkboxes are marked if you want to back up all contents of the mailbox, including hidden items like rules and items in the "dumpster" (the container used to hold items after they're removed from Deleted Items until the retention ...