It just keeps getting better! I had previously posted an entry on Sidewalk Greening in San Francisco explaining that the city offered support in helping to expediate permits to take up sidewalk and offering a resource list. They have now gone a step further and offer FREE Saturday (9am-10am) workshops to any aspiring concrete gardener. They are held once a month from February through November 2011. Clicking on the photos should allow you to read the exact dates with a more detailed explanation of the workshops.
To the sidewalk on my block: Be afraid... Be very afraid. We're coming for you.