You don't specify which city you live in, but since you say it's bike friendly, there's a good chance that there is a local bike group that focuses on raising awareness for cycling issues and advocacy, possibly a bike co-op shop. Often these groups put on bike safety classes, or classes on learning how to ride confidently in traffic. Just Google your city name + "bike advocacy" or "bike commuting classes." You may also want to go into the local forums here and see if there are any discussions pertaining to your city, so you can talk to the people who know what it's like where you are. Sometimes regular bike shops (even REIs, if you have one of those nearby) do classes like these.

Besides all that, some basic advice--start riding on the weekend or some other time when traffic isn't as heavy as it is during commuting times. Start to go out for short rides, find which streets and routes are the most comfortable for you. Good luck!