I noticed a lot of people get confused on what to do when they see a stray or feral cat. I am currently working with several ferals, and wish to offer my advice and share some resources with everyone!
*Feeding: If you have chosen to feed a feral cat that is still shy, make sure you are keeping an eye on where the cat is, and try to put it's bowl near the cat's 'hideout.' Every time you put food into the bowl call out 'kitty kitty kitty' and soon the cat will associate your calls with food. Wet food is best for any cat, but if you are feeding them dry food make sure they always have access to water as well since dry food can dehydrate a kitty.
*Taming: If the cat is letting you get close during feeding time, attempt to softly stroke it from behind. Do not approach the cat from the front as this is threatening to them. Do not stare into their eyes either, make sure to blink frequently and look away often. If the cat is approaching your hand, keep your fingers curled in and allow the cat to sniff your fist. Getting used to your scent is a big step, and will take the kitty sometime especially when left outdoors.
*Kittens: If you wish to tame feral kittens that you have found or 'rescued' follow the steps here: http://www.feralcat.com/taming.html
I have recently tried these out on a six week old kitten, and it only took her a week to become a loving little kitty.
Some ferals can become tame, others cannot. If you can, PLEASE Trap, Neuter, and Return the cat to where it 'lives' this is the most humane, and effective way to control feral populations.
If you need help financially for the ferals try contacting a local rescue group, humane society, or start a fundraiser (I HAVE!).
Helping feral cats is a difficult, and often taxing job, but remember these colonies occur from abandoned, neglected, and forgotten pets.