Bob Jenkins's lookup3 hash algorithm .

Performance

AMD Athlon XP 1.620Ghz
Power4 1Ghz
UltraSparc
III 1.2Ghz
Intel C/C++

CRC32	         6.42	 5.66	 5.66	 5.67	 14.06	 8.75
One at a Time	 5.76	 5.66	 5.66	 5.69	 12.79	 5.57
Alpha Numeric	 3.29	 4.06	 4.06	 5.67	 10.26	 5.52
FNV Hash	 4.88	 4.84	 4.83	 4.87	 8.92	 11.98
Bob Jenkins	 2.08	 2.36	 2.03	 2.07	 6.16	 3.08
SuperFastHash	 1.54	1.92	1.59	1.34	3.71	 2.15
Data is time in seconds taken to hash a random buffer of 256 bytes 5 million times. 

From: http://www.azillionmonkeys.com/qed/hash.html

Install

/[PHP_PATH]/bin/phpize
./configure --with-php-config=/[PHP_PATH]/bin/php-config 
make
make install

vi php.ini

add line:

extension = "lookup3.so

Example

<?php
$r = lookup3_hashlittle("aaa");
echo $r;
?>

Reference Documentation:

http://www.burtleburtle.net/bob/hash/doobs.html