I have used www.urinegone.com
http://www.fanciers.com/cat-faqs/misc.shtml

Removing Urine Odor
For fresh urine: clean the spot with any good carpet shampoo (Spot Shot is
one). Then soak it with plain old club soda, leave it for about ten minutes
and blot it up.
If the urine has soaked the pad and the floor below that, it will be
difficult to remove the odor regardless of what you use.

To find spots if you're not sure where they are, get a UV lamp that has the
filter built in (to eliminate any remnant visible light). Urine fluoresces
in "black light." You can get them at hardware stores. There are also UV
lamps in hobby stores and places that cater to spelunkers and rockhounds,
but they're more expensive. The UV source is safe as long as you use the
longwave lamp and not the shortwave lamp used for tanning.

Enzymatic products
Products that remove odors: Nature's Miracle (carpet, has 800 number);
Simple Solution (carpet and other items); Outright! (carpet); Resolve
(carpet, perhaps other items); Odor Mute (originally for deskunking dogs,
has other applications, leaves white residue, works on concrete). Odor
Abolish, by Endosome Biologicals, may also be useful. These products use
enzymes to break down the odor causing compounds in urine and feces, and are
quite effective.
When using enzymatic products, it is important to use freshly diluted
enzymes, let it soak in as deeply as the urine has penetrated, and *keep the
area warm and wet for 24 hours*. Chemical reactions, including enzymatic
reactions, go faster at higher temperatures. Unfortunately, most enzymatic
reactions don't do well much over 102F (38-39C)-- so not too hot. Try
covering the area with towels soaked in plain water after applying the
enzyme, then a shower curtain or other plastic over that to make sure the
area stays moist.

The enzymes in laundry products are the same as those in the expensive
odor-killing products, but they cost less than 1/3 as much. They work just
as well. Biz is one product. You'll find it in your grocery laundry section
with the pre-soak laundry stuff. Remember, you have to soak the area and
then cover it to keep it from drying out. The smelly area must be wet with
the enzyme for 24 hours or more.

Launderable items
On launderable items: put in the washing machine with a cup of vinegar and
no detergent, then wash again as usual.
Concrete
If you have concrete (eg, in the basement) into which urine has been soaked,
this can be difficult to remove, as unsealed concrete is very porous. You
will have to neutralize the urine and then seal the concrete properly. A
specialty cleaning service is probably the best way to properly neutralize
the urine in the concrete. Vinegars and other cleaners may help, but only
temporarily. Odor Mute is reputed to work on concrete. Improving the
ventilation may also help. In extreme cases, pouring another 1/4-1/2 inch
layer of concrete over the original concrete will solve the problem.
Hardwood floors
Hardwood floors that have been stained with urine can be difficult to clean.
First treat with an enzyme-based product such as Nature's Miracle to remove
the odor. You can find wood bleaches and stains at your hardware store: you
may want to consult with one of the employees on what is available. You will
need to remove any varnish or polyurethane from the area, sand it down a
bit, bleach and/or stain it, and then apply the protective coat. There are
also professional companies you can consult. In severely stained cases, you
may have to replace the wood.

Soak up as much as possible with kitchen paper even to the extend of
standing on the paper to draw up as much as possible. Then with a BARELY
damp cloth of white vinegar wipe gently over the area. Don't wet or soak the
carpet. Leave a few minutes and then sprinkle liberally with baking soda
over the area to a thickness of around 3mm and extending a good 50mm beyond
the stain area.  Leave for several hours.
Then vacuum the powder off gently - don't compress the carpet too much if
possible.

A sun lamp  on the area may help as well.

You may have to repeat the treatment several times every other day for a
week. It's not easy to remove cat urine odours, nature has designed it to
hang around a long time!!