The ASPCA's Animal Poison Control Center is a great resource for animal toxicities.  On the homepage there are several links to lists of toxic plants.  For specific toxicities you can call the center and talk to a veterinary toxicologist--there is a charge for this service.
http://www.aspca.org/site/PageServer?pagename=pro_apcc
A common houseplant very toxic to cats are plants in the Lily family--they cause severe kidney failure. 
You'll find this website very helpful.

 One that of know of is pointsetters

 I was told that Spider plants were poisonous to cats too!!!

 These are all the plants that are toxic to cats/kittens.
The following plants or parts of them  (bark, leaves, seeds, berries, roots,
tubers, spouts, green shells), can be toxic to your cat.
Check with your veterinarian before having them in your home.
Or if you still think you must have them, keep them safely out of reach!



Almond (Pits of)
Aloe Vera
Alocasia
Amaryllis
Apple (seeds)
Apple Leaf Croton
Apricot (Pits of)
Arrowgrass
Asparagus Fern
Autumn Crocus
Avacado (fuit and pit)
Azalea

English Ivy
Eucalyptus
Euonymus
Evergreen