Windows Vista has a new search engine that is extremely powerful and useful. You can search metadata, IM's, pictures, documents, email, etc. If it is in your operating system, it can be found. The instant search or as-you-type search is one of the most powerful features of the operating system. The Search box is located at the bottom of the Vista Start menu and has advanced searching available as well.
Download my video blog on how Search works in Windows Vista.