Yep our source of weather info has now removed their free API so we are looking at alternatives
What about:
NOAA
NOAA National Weather Service (NWS) API Profile
NOAA's Weather and Climate Toolkit (Viewer and Data Exporter)
WeatherBug
WeatherBug API Profile
Weather API for Programmers and Developers - WeatherBug.com
Google’s Secret Weather API
Animaonline Weather API
Accuweather
AccuWeather API Profile
Weather Central
Weather Central API Profile
ALL
API Directory - ProgrammableWeb
Looks like TWC.API is subscription only now $19.99 a month. The Weather Channel Launches New API for Developers. Posted 10-25-11
Wunderground would be my first, but a max of 500 hits a day is a little weak...
This is my favorit too, I've been so bold to contact Weather Underground, there API can be used for free under circumstances. (for non profit applications)
They told me with some "rules" to follow Mediaportal will be able to use this API for free. (rules are about visabilty of the wunderground logo and website etc,)
http://www.wunderground.com/