don't put an animal in the paper for free!
if someone is not willing to pay for an animal, how can you be sure that they will be willing to pay to take care of it?
how do you know they wont just get bored of this thing they got for free?
try other animal shelters, especially no-kill shelters. you will always be charged, because shelters need to bring in money so they can support all of the animals they keep
as far as i know, there is no organization that will come pick up your kittens
preferably, put ads in the paper, on craigslist, etc for kittens (figure out a price)
screen the owners to make sure they are suitable
it is a lot of work, i will admit that, but it is worth it knowing that you did the best you could to help place these kittens in good homes
also, get your cat spayed. your local humane society or other organizations will offer that free, or at a reduced price. the world does not need extra kittens!