Here is some software that you can use to run your own search engine like google, yahoo, msn etc…
http://www.aspseek.org/
http://www.devarticles.com/c/a/HTML/Building-A-Search-Engine
http://www.find.vg/
http://www.dataparksearch.org/dpsearch-install.en.html#sqlreq
http://lucene.apache.org/
http://www.digg.com/programming/Building_a_Simple_Search_Engine_with_PHP
http://swish-e.org/
