You need to verify the settings under Tools | Options. Go to the 'Other' tab and click the Auto-Archive button. If it is set to run, you may not have the "Prompt before AutoArchive runs" option checked that would give you the visual queue that it is happening.
Further on down the dialog box, you will see the "Move old items to:" radio button and under it, a path to a .pst file, usually something like the following: C:\Documents and Settings\userprofilename\Local Settings\Application Data\Microsoft\Outlook\archive.pst
If you copy that path (highlight it and hit Ctrl+C) to the clipboard, you can then exit out of the dialogs and click on File | Open | Outlook Data File...
Paste (Ctrl+v) the path in the File Name text box and hit "OK", your PST with the AutoArchived mail in it will appear on the list of mailboxes and folders on the left of the screen.
-joe |