I did that for awhile and I have to say....it was a LOT harder than I expected. My first assignment was to foster a family of ferals.....mom and 4 kittens and try to tame them as much as possible so they could be adoptable. I had to keep the foster family away from my cats (I only had Leo and Shelby at the time) so it was quite a challenge keeping 5 kitties in my bedroom for several weeks. My house isn't that big.....so I didn't really have a good "space" to keep them in. If I had a bigger house....I might try it again.
I was able to tame the mom and two of the kittens and they became very loving...but two of the kittens never came around during the time I had them. I did enjoy the experience....but I don't think I'd do it again unless I got a bigger place and could give them their "own" room. I didn't sleep for weeks with 4 feral kittens running all over my bedroom! Plus, it was very distressing for my cats and it took awhile for Shelby to forgive me.
Here's some pictures of my foster babies. You can probably guess the two kittens who were able to be tamed.
Freckles and Cheeser
Cheeser looking in the mirror
Freckles, Cheeser, and Ninja on the floor.
Summer and Freckles
Ninja and Summer....the two solid dark gray babies never would let me get too close. But Cheeser and Freckles became little sweethearts. Fostering is a big responsiblity and I admire you for doing it.