I'm not a big fan of bikely.com. I find it cluttered with dangerous routes posted by braggarts. The cycling layer on maps.google seems only to work for North America. Calling bike shops yields blinkered responses. I would propose an international bike friendly star rating system for cities, but doubt suitable terms of reference could be agreed on: I can imagine tokenism pushing one city's score higher, while another city's genuine but less obvious appeal to real riders, might go unacknowledged.
The answer, I think, is a review site, where riders/writers actually go out and road test various cities. I'll road test my own for you all in coming weeks, as an example. End of trip facilities, on road routes, driver attitudes, designated routes, informal routes, numbers of social and sporting bike groups: all could be mentioned as part of a comprehensive written review, that would help the cycling class in their gradual migration toward cities that want them, and away from cities that don't.