Scratching is a normal feline behavior. The difficult part is training them to use something other than furniture or door frames.
Other Scratching Options
The best choice is to offer a sturdy scratching post from the time your pet is a kitten. Play with him or her on and near the post, offer treats, toys and praise when your pet uses it.
Many cats will be attracted to scratching posts that have been rubbed with cat nip. Some cats will scratch on cardboard boxes or scratch pads, while others will only use tall, sturdier posts that do not tip over.
Minimizing Damage from Scratching
Older cats that have developed a furniture damaging habit will be harder to train to a post but can still learn.
Frequent nail trims can decrease the damage caused by scratching. Some owners find help with a soft, plastic nail cap that is temporarily glued to each nail. This can have mixed success as the cats may still scratch (with plastic blunted nails), and the caps need frequent reapplication.
Covering a favorite scratching area with something slick or tacky like plastic sheeting, or double stick tape may discourage the behavior as well.
Other Feline Behavior Issues:
Is my cat in heat?
My cat is spraying!
My cat isn't using the litterbox