Browsing through the pages on the Google Toolbar API (http://toolbar.google.com/buttons/apis/howto_guide.html) I ran into an example of a custom button fetching the weather for a certain zip-code. In the comments for the code for this button the following can be read:

// Script to convert Google xml weather interface to custom buttons AtomFeed 1.0
// Sample input at http://www.google.com/ig/api?weather=94043
// To see sample output, run this script with ?zip=94043

Anybody know anything about this Google xml weather interface? I think it would be pretty cool to be able to use it to grab the weather predictions to use for certain custom applications.

Nevermind, experimenting with the url from the example I am already able to fetch some interesting results:

www.google.com/ig/api?weather=Madrid
http://www.google.com/ig/api?weather=maastricht,netherlands

I wonder what other parameters you can pass to this API.