just put the full URL in the SRC part.
<frameset rows="25%,*" framespacing="0" frameborder="0">
<frame name="top" src="http://www.whatever.com/top.htm" marginwidth="0" marginheight="0" scrolling="no" frameborder="0">
<frame name="body" src="http://www.whatever.com/body.htm" marginwidth="10" marginheight="0" scrolling="auto" frameborder="0">
</frameset>