The following code in the default document will hide the URL to where the request is being redirected:
<html>
<title>Welcome to my site</title>
<frameset cols="100%,*" border=0 frameborder=0
border=0 framespacing=0 scrolling="yes">
<frame src="http://source.domain.com"
name="AddressHidingFrame" marginwidth=0
marginheight=0 frameborder=0 noresize scrolling="yes">
<frame name="needed4Netscape2Work" marginwidth=0
marginheight=0 frameborder=0 noresize?
</frameset>
</html>