Thanks for all the comments. I will elaborate slightly to give everyone an idea of what is going on. Basically I need to create a dynamic visualisation which sits in the active desktop, basically behind the desktop icons and in front of the windows wallpaper. Windows lets you define a web page which can be displayed in this way. The application itself can sit on the local users computer, rather than actually being downloaded via the web. It will be retrieving data from a variety of sources. If there is another way to do it then that would be good, for example writing another active desktop application which people can use.
The user has to be able to resize, move or get rid of the visualisation if they wish to do so. Best, rod -- http://mail.python.org/mailman/listinfo/python-list