Ramsey county has several bicycle and trail maps online, but they're poorly organized and hard to find. These links may not persist, but they are a start:
Ramsey County ALRC: Active Living Ramsey Communities
Ramsey County Bike facilities and Gaps map (PDF)
They have some Google maps "rambletown tours -- not terribly useful, but nice to see ...
Now you can visit Ramsey County's Gateway, Bruce Vento, and Indian Mounds trails from your computer. These maps are created from a web application that automatically generates trail maps from pictures on a web album that have been geocoded.
Other sites list more maps
Pedestrian Trails Map (5 mb PDF file)
then there are regional trails
Lastsly, there's a Hiking and Biking brochure.