Hi, this Tut was great. But as many as mentioned so far, there are quite a bit of extra thing that can be done. One of the main issue I have with this example, is that it only search for one word, and without true relationship without each otehr, except the amount of time the word is present in the text.
I would like to suggest a php search engine that I wrote (it's GNU licensed) that include full on-screen installation, ability to create different index zones on your website (perfect for multilingual sites), natural language search and query expansion using MySQL 5.0+, great on-screen stats and report about your user's searches, aggregate userS' search and suggest complementary terms of search to ease your user's experience, and much more. Have a look at http://blog.dstmichel.ca/index.php/2007/05/14/11-invenio-a-php-web-search-engine
And feel free to play and learn with all the included well-comented files.
I would of course greatly appreciate your comments and would gladly help if you need assistance.