$ perl -v | grep built
This is perl, v5.8.5 built for i386-linux-thread-multi
$ php -v | grep built
PHP 5.1.6 (cli) (built: Jun 17 2007 11:44:56)

##</code><code>##

export PHP_PREFIX="/usr"
export PERL_PREFIX="/usr"
$PHP_PREFIX/bin/phpize
./configure --with-perl=$PERL_PREFIX --with-php-config=$PHP_PREFIX/bin/php-config
make
sudo make install

##</code><code>##

$ grep -i extension /etc/php.ini | grep -v '^;'
extension_dir = "/usr/lib/php/modules"
extension=perl.so

##</code><code>##

$ ll /usr/lib/php/modules/ | grep perl
-rwxr-xr-x  1 root root 150234 May  6 08:56 perl.so

##</code><code>##

$ cat perl.php
<?php
$perl = Perl::getInstance();
?>
$ php perl.php
PHP Fatal error:  Call to undefined method Perl::getinstance() in 
perl.php on line 2

##</code><code>##

$ cat call.perl.from.php
<?php
#$perl = Perl::getInstance();
$perl = new Perl();
$perl->eval("
print \"Executing Perl code in PHP\n\"
");
?>
$ php call.perl.from.php
Executing Perl code in PHP