The best thing to do is contact your local SPCA shelter; they always have abandoned kittens looking for homes. Check out your local papers/shop for any advertisements also. And let friends know you are looking for one; they may know someone who is looking to home kittens.
If you get the kitten from a private owner be very sure they have the sex right before taking her if you're adamant you want a female. I checked out some pictures on the internet before I went to get mine as I preferably wanted a male cat. If you get the cat from a shelter I would hope they have had her checked out by a vet etc. Make sure the kitty is at least 8-10 weeks old!