Hello potguy,
As there are many different variations of search engines such as how they search, how they determine results, and how they display them (many with ads, etc), we do not endorse any specific scripts of programs. However, you may want to search script sites where they have many different selections. You can compare the features against your needs and select the correct one for you. Many content management systems such as WordPress and Joomla have them built in. One recommendation for a third party would be the Google Site Search. Other scripts can be found at sites such as Hotscripts.com
Best Regards,
Scott M