The user has to enter City, State (in US) and City, Country (for other countries)
There's a limit of 500 requests per day, and 10 requests per minute. Details here.
It provides support for about 80 foreign languages, but not many as that provided by Google. You can view the entire lists of countries here: Language Codes
Think this is to date the best and easiest-to-use weather API available. Even Google is using this for its iGoogle now.
It's free! (at least for the first 500 requests)
The city name now display correctly in your language. For the Google Weather API, the city name is always in English.
If, say you are from Italy, you can set the "Default Country" in the parameter page to "Italy". In this case, the user only need to enter the city name e.g. "Rome", without the need to enter the country name every time.