If you speak German and you have about an hour of time, you should watch the video of the presentation of Uwe Vetter at the 23C3 on house searches and how to deal with the police in such situation, especially if “you have nothing to hide”.
Uwe Vetter is the author of the law blog, a well-recognized blog on German law and justice. He is lawyer and has been blogging for several years now.
The video is really entertaining and informative with a lot of nice information and background stories about a situation I hope I’ll never face. It covers the situation in Germany, but I expect that many of the advises given also apply to Austria and other countries.