Anyone with a Google account can create a Google Custom Search Engine. This service enables you to limit your searches to specific websites or even specific web pages. This makes it much easier to get more precise result while searching in specific subject areas as you can include the sites you want to search and specifically exclude sites as you require. You can also personalize the look and feel of your search engine. A good set of instructions for setting up a Google Custom Search can be found at O’Reilly’s OnLamp.
One really good example of how to use the custom search engine is Ted Tjaden’s “Search Canadian Law Firm Websites, Blogs & Journals” which will search 79 selectively chosen Canadian law firm websites, 205 Canadian law blogs and 20 Canadian law journal websites.