From CAWS, an animal rescue.

Declawing! What You Need To Know

Declawing is akin to cutting off half the cat's toes. When the end digit, including the claw is removed, the sensory and motor nerves are cut, damaged and destroyed. They do not repair themselves or grow back for many months. Following the surgery there is a wooden lack of feeling, then a tingling sensation during the long convalescence while the cat must walk on the stub end of the second digit. Remember that during all this time the cat may not "rest" his feet as we would after a similar operation but must continue to scratch in his litter box, walk and attempt to jump as usual regardless of his pain. Most veterinarians in other countries refuse to do the operation.

Besides the physical mutilation, consider what declawing may do to the cat's emotions, the personality changes that may occur. Knowing he has not the means to defend himself, some cats follow the precept of the best defense is a good offense, and will bite at the least provocation (and it may truly be the least provocation.) Often times cats become "biters" when they can no longer rely on their security of their claws. Others become depressed and lose the loving personality that made you choose him to start with. Many cats also experience litter box problems.
If you really love your cat, you will want him to lead a long, happy life, giving and receiving love and affection. If you really love him, and care about him, don't declaw him. There are many alternatives such as nail trimming, training and soft paws claw covers. If you feel you must have a cat that is declawed due to outstanding circumstances please adopt a cat who has already been through this procedure rather than subjecting another one to it. CAWS has several cats who are already declawed. Please visit http://www.caws.org.