Street photography is exactly what it sounds like: taking your camera out in the street and taking photos. Of what? People, architecture, geometrically pleasing shadows: it's up to you. The two things you have to consider first, though, are the law and your own personal ethics.
In a nutshell, with a few exceptions, as long as you're standing on public property and the subject of your photo is also on public property, you can photograph whoever or whatever you like. In New York, where the law is similar, photographer Bruce Gilden exploits this to the max by pointing his camera right in the face of passersby, flash and all. Incredibly, at time of writing, he is still alive.
The reason people like Bruce Gilden are so rare is that most of us have a pretty healthy fear of confrontation and we ceratinly don't enjoy pissing people off. We don't want someone coming up to us and asking why we're taking their photo. So if we want to have people in our shots we have to:
a) Ask their permission before. This will give is us a posed street portrait, which may look unnatural or may look fantastic, depending on your subject. Gabrielle Motola is very good at this type of shot.
b) Take the photo first and ask their permission afterwards. Probably the most ethically sound way to take and use an unposed street photograph, but uncomfortable for the photographer and probably also for the person being told "I just took your photo..."
c) Shoot from a discreet distance. Don't ask for permission, either before or after.
I personally choose C, but hear me out. Like I said, legally I can take photos of whoever I want, however I want and stick them online, but I don't allow myself that much freedom. I set myself the following rules:
Don't take photos which show people in a bad light.
Don't photograph vulnerable people or children.
Where possible shoot people in silhouette, or with faces turned at least partially away from the camera.
If faces are visible use only a wide shot (ie faces are not close up and make up a very small percentage of the frame).
This is by no means a list of suggestions. Each photographer will have their own set of ethics, and I'm not here to question or influence anyone else's choices. My own approach to the art may well change over time.
Anyway, here are some of my images, which all adhere to the aforemtioned rules. I hope...