This link is for the Duluth / Superior area bike map. It's very detailed and will help you get from point a to point ? and everywhere you need to in between. I also thought I'd make a note of it due to the fact that pretty soon the snow's going to be falling and if you ride in the winter, you may be thinking about alternative routes (riding on London road with no shoulder and a big bank of snow does not sound too fun).
Another site I'd like to point out today, Duluth Trails, is a site detailing the various trails in the Duluth area. The Duluth News Tribune (I believe) created it with help from some other sources. It's very nicely done and I plan to use it to find some future Tag pictures.
I hope you can benefit from these links and I hope you keep having fun Biking in Duluth.