include 'akismet.class.php';

// Load array with comment data.
$comment = array(
                'author' => 'viagra-test-123',
                'email' => 'test@example.com',
                'website' => 'http://www.example.com/',
                'body' => 'This is a test comment',
                'permalink' => 'http://your-domain.com/path-to-your-comment-page',
                'user_ip' => 'an-ip-address', // Optional, if not in array defaults to $_SERVER['REMOTE_ADDR'].
                'user_agent' => 'user-agent-string', // Optional, if not in array defaults to $_SERVER['HTTP_USER_AGENT'].
        );

// Instantiate an instance of the class.
$akismet = new Akismet('http://www.yourdomain.com/', 'YOUR_WORDPRESS_API_KEY', $comment);

// Test for errors.
if($akismet->errorsExist()) { // Returns true if any errors exist.
        if($akismet->isError('AKISMET_INVALID_KEY')) {
                // Do something.
        } elseif($akismet->isError('AKISMET_RESPONSE_FAILED')) {
                // Do something.
        } elseif($akismet->isError('AKISMET_SERVER_NOT_FOUND')) {
                // Do something.
        }
} else {
        // No errors, check for spam.
        if ($akismet->isSpam()) { // Returns true if Akismet thinks the comment is spam.
                // Do something with the spam comment.
        } else {
                // Do something with the non-spam comment.
        }
}