Very similar to BookmarkQ but much easier (IMHO)
Type in your URL then drag and resize the highlighting box over the area you want to highlight. Press the Test it button to test it out then use the Copy URL button to make the link.
Works very nicely indeed. Here is one I made earlier – http://infocus.cc/?url=http://www.cricinfo.com&p=1200&b=ie&l=481&t=314&w=324&h=121
See on infocus.cc