iWeather uses the weather feed from yahoo (or weather.com). When you run iWeather, you need to connect to the internet. Same for the Settings.exe.

Release notes:

How to:
======
1. open Settings.exe
2. enter your LocationID
3. press ENTER
4. press Done-Button
IMPORTANT! It is nessessary to stay online!

Things to do:
==========
– fix battery-bug in Settings.exe
– adding more than one location
– open settings by pushing the “i”-button
– caching data for offline use
– maybe integrating settings into iWeather
– maybe different language support
– …

v0.1
===
– first release
– only one city-weather is possible
– search in Settings.exe only writes the LocationID (e.g. USNY0996) and the displayed unit into the city.xml (you can find your LocationID at http://weather.yahoo.com )
– Settings.exe gives as validation the city-name to the entered LocationID.
– it’s not possible to start settings from iWeather
– iWeather will automaticaly start, after pushing “done”-button in Settings.
– background-image and icons will change after sunset or sunrise of the selected location
– both apps can be closed by pushing the battery on the upper right corner

http://forum.xda-developers.com/showthread.php?t=441825