OE message backup/move

["Gilbert Strang" <gstrang@xxxxxxxxxxxx>]

How to backup/move thousands of messages of Outlook Express to a different
PC?
-both running WinXP Pro.
-different PC name, different login name, different Outlook Express default
 e-mail account.
-the original, to be backed up one contains several extra folders in its
 'Local Folders', while the new, to be moved to one, maintains the default 
 folder structure.

Thanks!