We too had chickens at one point. My mom liked them and so from the time I was 16 till just recently my mom had them around. We built them a pen about 8 ft. by 8 ft. and then would also allow them to roam the back yard. They stayed in the pen at night, on rainy days, and days we weren't going to be home. We never ate them and in fact I hate eggs and my mom is allergic to them so we rarely used the eggs. They were mostly there as pets as my mom liked to go feed them and watch them scratch and peck around the yard. We had the bantam varieties (Cochin and silver sebrights) and a few Araucanas for the green/blue eggs. Like Griff we found the hens to be very good natured and the roosters to be a little mean at times. If you live in a real urban area I don't recommend roosters as they will crow at 4 AM (and sometimes earlier) and it will bug your neighbors.
Here are two sites that have some info on chickens. The first is the
American Poultry Association's article on having chickens in an urban setting. You have to scroll down a bit to get to the article. The second site has
photos of different chicken breeds. Its not a complete list as they don't have any photos of breeds that only exist as the bantam (small) breeds. But still its nice to look at the photos.
Here is a link to a
hatchery that has a bunch of photos as well, plus you can order day old chicks from them.
Prob. more chicken info then any of you wanted to know. Those are just site I found with a quick google search, so there may be better stuff out there.