Cycle maps

Dear lazyweb, is there a website where I can look up cycle routes? Similar to googlemaps search, but specifically for cycling rather than walking. I've looked and looked but I'm not coming up with anything.

(Or alternatively, do any of you have good routes to Harston (where I'm sure I've been by bike before, isn't it on the way to Duxford? And it has the pub where they do the rabbit pie Jon's always talking about (seriously, he even has a 'rabbit pie' course he teaches (no, not really))) or Cambourne?)