Hi, I'm Maureen and I'm a fosterer for Croydon Cats Protection. I'd always wanted to be able to help CP out with voluntary work but I work full time and, as I'm self-employed, even weekends can be spent in front of the laptop. Also I have two cats (adopted from CP) and would love more, but my two would resent another permanent member of the family. So the perfect solution was fostering.
As I have cats I use a spare bedroom for the foster cat (usually one cat at a time unless they come as a pair). The room is full of toys, bedding, catnip and scratching posts cat heaven in fact. Once (if) they are confident and want to expand their territory, I let them have the run of the top floor of the house. As we work outside the house all day, I only look after adult cats they usually sleep through the day and are ready and able for play sessions and cuddles in the evenings. 
I've been fostering for about 18 months now and haven't looked back. I've had poorly cats, terribly shy cats and some that are just plain bonkers. Every cat is different but the warm feeling I get when I finally gain the trust of a new foster is definitely addictive. Although I've been known to shed a tear when they leave, the knowledge that they are going to lovely new homes and that I'll be able to offer a foster home to another cat makes it worthwhile. Although I've always had cats, I've learnt so much while I've been fostering.
The support you receive from the other volunteers is fantastic and you're never alone. Another unexpected and welcome side effect of fostering is that I've made new like-minded friends.
I highly recommend fostering. Why not give it a try?