I started bicycle commuting just over a week ago. So far I've been doing it the easy way by not riding during morning or evening rush hour. That's been easier as I have fairly flexible hours. So I arrive at work after the majority of the morning rush and leave before or after the evening rush.
It's been easier to get accustomed to riding in traffic in this fashion since the street I ride along is fairly busy. The good thing is that there are plenty of stop lights so people can't really go that fast, the city buses slow everything down to a crawl anyway and there are pedestrians for everyone to worry about.
After all, would you stick a 16 year old who just got his driver's license in a car in the middle of the afternoon rush in a major city and tell him "Good luck!"