Wash the area that you're going to repair with leather cleaner. You probably want to test it on a patch of the furniture that won't show just to be sure that you're not removing color in the process. Wash the whole panel even if you only have a few widely spaced scratches; this will make the adhesive and protectant stick better.
Push the "tags" (or pieces of leather that stick up from the cat scratches) down with a pin or needle. Make sure you can do this with as little visibility as possible. In short, be patient. One technique is to tease the tags up and then use the side of the needle to lay them down flat.
Use the dye or shoe polish (that matches your leather, of course) to blend in and make the scratches disappear. You may want to apply a thin coat of dye and then blow it dry with a hair dryer before applying another coat. Keep applying thin coats and drying them until you can no longer see the scratches.
Apply leather protector over the affected area after it has had time to dry overnight. It's always best to apply a thin coat of the various products listed rather than globbing on a lot with the hope that it'll blend in. Leather is such a smooth surface that it's really obvious when imperfections aren't fixed carefully.
Spray your cat with water directly on its head every time it approaches the furniture. It will soon learn not to mess with you, or the furniture. You can also spray your furniture with spray available at pet stores that deters cats. These sprays have chemicals that cats do not like, and they won't come near anything sprayed with it.
