Good place online to find old shower valves

Does anyone know of a good place to find replacement shower/tub valves online? I have used ********solutions.com in past but can't seem to find these suckers anywhere. Specifically I am looking for American Standard Colonial replacements.

Thanks.

You don't mean a whole valve, but just stems for American Standary Colony? Those are not hard to find. google.

Correction

Right, the stems and trim. Actually found out today it is a Kohler valve that just looked similar to the AS valve. House built in the 1950's so had to order them from a local hardware store. I would like to be able to just go online and order somewhere but haven't found a good place to find them.