Getting a Kitten

Follow the instructions for a gradual introduction. My experience has been that, generally speaking, well-socialized female cats often accept kittens without too much fuss, especially if they've ever had kittens themselves. Initial behavior could be hissing or bopping kitty on the head with a paw. Your cat will do this to show dominance and you should just ignore it unless she is being vicious about it.

I have a thread from a month or two back outlining my steps/experiences introducing my new female kitten to my 2 year old female cat.

Life is all harmonious now (I followed the steps in the link MowMow posted to a tee).

They now cuddle and play, and pretty much love each other