Some products to remove cat urine odor include Anti-Icky-Poo by MisterMax and Bramton Simple Solution. These are enzyme-based products that break down the cat urine and eliminate the odor-causing parts.
Cleaning cat urine stains and removing the odor is best approached as a multi-step process. For older stains, use a wet vac to clean the area, but avoid using a steam cleaner. After as much of the urine as possible as been removed, apply the enzyme-based cleaning product to get rid of the odor. Finally, apply baking soda or an air freshener with a baking soda base to remove any lingering odor from the air.