Unlike previous version of OS X, Leopard doesn't come with PHP's PEAR repository installed by default. Luckily, installing is quick and painless. From a command line:
curl http://pear.php.net/go-pear > go-pear.php sudo php -q go-pear.php
Just press enter to select all the default choices except for the installation directory. For that, use
/usr/local. (Thanks, Steve.)
Next we need to modify our
php.ini file to include the new PEAR files:
sudo cp /etc/php.ini.default /etc/php.ini
/etc/php.ini and change
;include_path = ".:/php/includes"
include_path = ".:/usr/local/share/pear"
Restart Apache and you're done!