From the group behind Mind the Gap in San Fransisco:

MIND THE GAP – URBAN BIKING: Overcoming Your Fears from Laura J. Lukitsch on Vimeo.

Best tip, ride with friends! And friends, ride slower than you are used to. Taking up a bike for the first time in years is scary. But if you go slow, take breaks when needed and pile on the encouragement, your friend will likely find that biking is neither hard nor scary.