You can do it with FrontPage 2003.  Open your SharePoint web site in FrontPage, go to "Tools > Server > Backup/Restore Web Site" option, and save the site as a *.FWP archive on your local system (or extract from it in case of restoring).

This Microsoft article shows in detail how to Backup/Restore/Move a SharePoint Services site with FrontPage 2003:

http://support.microsoft.com/default.aspx?scid=kb;en-us;825536