I'm fairly new to San Francisco. I've taken up biking the last few months while I have been here, and I want to do a variety of rides around the city. I am having no trouble making up my own, but I have been unable to find a good resource that has routes already mapped out. If anyone has any websites they can point me to, that would be very helpful.
The San Francisco Bicycle Coalition has a SF Bike Map & Walking Guide that they'll give you if you join, or you can buy it at just about any bike shop in SF or online. (and the online version at that link isn't bad). It's got bicycle-friendly routes color-coded. They also have various organized rides and other events.
Google Maps can give you bicycling directions anywhere, but is probably extra good in SF.
There's a bunch of different cycling clubs in or near SF, but I think many of their organized rides go outside of SF. (SF is only 7 miles across). If you just want to ride around on your own, you can probably find out the routes for some of these rides.
I've been enjoying Ride with GPS, which is fairly new, and a mash-up of googlemaps, gps, and user generated routes.
One thing you can do with Ride with GPS is to plot out your own routes and also, there are over 150 user generated routes in the San Francisco area. Also note, you don't need a GPS device to use the site. I've used it to plot out ideas and to discover rides in my area that I hadn't thought of.
The guys behind Ride with GPS are very responsive and constantly improving the site. So, it's worth checking out.
Here are some rides I've been on lately that might interest you, depending on your level of fitness.
Marin county, just north of the Golden Gate Bridge, has some absolutely beautiful cycling. The climb up Hawk Hill isn't too long, and offers some amazing views of the city and the bay. The Paradise loop goes through Tiburon via gorgeous windy coastal backroads and doesn't have too much climbing (the Camino Alto climb can be skipped). Mount Tam feels like an endless climb, but the views from the top are simply breathtaking — all along Ridgecrest you can see the ocean and Stinson Beach on your right, and the San Francisco bay on your left).
I'll be doing the Roasters ride this Saturday or Sunday.