PHP Search Engine (SEARCpHp)

Features:
All PHP, indexing and searching, no reliance on outside programs
Index is text file, no dbms or databases
Index is completely portable, copy it to any machine using PHP and SEARCpHp, Unix or 'other'
You can index from file system, databases, the web, whatever. If you can access it in PHP, you can index it.
Search Engine Math Syntax: -not +must
Since it's PHP, you can hack the code
Knows if you are using PHP3 or PHP4, and will utilize the proper code
It's Free, and always will be, under the same license as PHP itself.