Three cats in mom's house, all would scratch anything and everything.
I picked up this scratching post:
http://www.amazon.com/gp/product/B00...ls_o06_s01_i00
And, once every couple of weeks, spray it lightly with this:
http://www.amazon.com/gp/product/B00...ls_o06_s00_i00
For the first week, cover up everything they would scratch (couch, chairs, etc) with blankets... So the only thing they have to scratch in the entire house, is that post. Try to give them some positive reinforcement anytime you see them using the post too (petting, attention, treats, etc).
After that, the cats never scratch anything else.