getting rid of fleas

I have recently discovered fleas on my cats.  I was reading your very informative articles and saw that this product, Precor 2000, is helpful in getting rid of fleas in the house, carpets and on furniture.  However, I read that the active ingredient is permethrin, which is toxic to cats.  If I spray it in the house, can it hurt my cats?  If it will, what can I use to get rid of fleas in the house so that the cats won’t get re-infested?
Thanks :)

More on permethrin alternative for use around cats