Oh, cool! How did you get them introduced? And how did you pick the cat or determine if they would get along? QUOTE]
I decided the younger the new kitten, the better for my current cat.
I hope I can post this link:
http://www.humanesociety.org/animals/cats/tips/introducing_new_cat.html
I followed this a lot and it worked out great!! There was a lot of hissing by my older cat, it scared me, but it's very normal and she was never aggressive to the kitten.
I didn't do the part about proping the door open, they just smelled each other under the door. The first few days my cat would walk by the door and hiss at it, but within a week they were playing with each others paws under the door and my cat would 'nap' outside the door to the room the kitten was in. That's when I knew it was time to let them run free(supervised at first). It was a month before I let the kitten roam the house free at night and while I was at work.