Hihi borix! =D
To find the code for the weather applet do this:
1. Right-click on the weather applet icon in the dock.
2. Select "Weather Docklet Settings..."
3. In the popup window click on the Weather Channel logo.
4. Once the Weather Channel website loads type in Holland in the "Enter city or US zip" field, and hit Enter.
(Tip: you can also search using Netherlands to get the Amsterdam readings)
5. In the resulting list click on the link saying "Hoek Van Holland, Netherlands".
6. When the page has loaded check the URL and copy the eight(8) characters after the last /
(usually four letters followed by four digits)
7. Copy/paste them into the applet code field and klick the Update button =D
Let me know how it goes! =D