The link to this is not available in the site settings. Thanks to http://msmvps.com/blogs/shane/archive/2006/07/29/moss-2007-save-site-as-a-template-missing.aspx for this workaround.
If your subsite is
http://portal.abc.local/sitedirectory/team/default.aspx
You would go to
http://portal.abc.local/sitedirectory/team/_layouts/savetmpl.aspx