Hi Rik, I agree that it is possible. However organizational change is probably one of the most difficult tasks, so don't expect it to be easy. In burocratic organizations the hierarchy is very important (which is not agile, but the status quo when you start), so you need support from the highest hierarchy level. Help those people understand the benefits. Good luck :)
Joshua and Ludwig, thanks for your replies. The website from the UK governement is very useful and it is interesting to see how they are promoting agile working. Do you know of any specific projects that are succesful?