Where can one go to find a zip code look up for another country?

First of all, the correct term is "postal code"; the name "ZIP Code" applies only to addresses in the USA or in the Philippines. Secondly, a postal code typically identifies a town, a part of a city, or in some cases a specific address. It does not apply to a whole country.

To find the postal code for an address in Another Country, search for that country's postal service's website. If they use postal codes, there will usually be a search function to find the code for that specific address.