Here is a nice compilation of breeds, including color pictures and descriptions of feather, leg, and egg colors, temperament, hardiness, their purpose, production, comb type, etc. It is great if you are trying to identify a breed as well.
This one is for chickens: http://www.backyardchickens.com/breeds/
Here is a nice chicken characteristic comparison chart: http://www.mypetchicken.com/chicken-breeds/breed-list.aspx
And this one is for other fowl. http://www.backyardchickens.com/breeds/poultry-index.php
Aracauna, Ameraucana or Easter Egger??? Here is an article that explains the difference of these breeds; http://eggcartonlabels.blogspot.com/2011/09/ameraucana-easter-egger-or-araucana.html
Here is another great chart with breed characteristics: http://www.ithaca.edu/staff/jhenderson/chooks/chooks.html
Here is some info on telling the sex of your chicks:
Here is a blog that helps you tell:
Here is a site that claims you can feather sex 1-3 day old chicks. I will have to try this myself!
I usually use the comb size and color, but that doesn't work on all breeds. Behavior plays a role too.
Note about Silkies: Silkies are really hard to tell the sex on until they are about 4 months old! Some of the indicators are; the males will stand very tall and erect, the girls will crouch down low; and the girls will hide under the males when scared, like sticking their necks under the males; I guess some say that if you pick up a silkies and set it down the girls will shake off, the boys will not.
If all else fails, there is a forum of experienced poultry people that you can ask: