Honest advice about a woman cycling in a city: It can be safe and manageable and even quite enjoyable. If you are really nervous, as others have said, read up on basic rules of vehicular cycling -- riding on the roads, following the rules of the road, as the vehicle you are. In most states it's illegal (and really dangerous) to ride on the sidewalks, so don't do it. In addition to looking at on line resources, you might look in your city to see if there's a biking advocacy group that teaches bike riding in traffic skills. Or, look around for some bad-ass bicyclist and ask her/him if they teach you the rules. Basically, you stop at stop signs and stop lights, signal your turns, ride a foot or so TO THE LEFT of the white line (that's correct, NOT in the shoulder, NOT on the side of the road, ON THE ROAD), and make sure you are visible to other vehicle drivers, especially at night. I've ridden year round for many years in many cities (including the one in which I live) and I promise that if you put the time and effort into learning to ride safely, you will have a blast, and also have totally badass, practically free, very practical transportation. Enjoy!!!!