$ldap_connection = ldap_connect('SERWER');

ldap_set_option($ldap_connection, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($ldap_connection, LDAP_OPT_REFERRALS, 0);
ldap_set_option(NULL, LDAP_OPT_DEBUG_LEVEL, 7);

$test=ldap_bind($ldap_connection);

if  ( $test ) { echo "OK"; }

$dn = "ou=xxx,DC=xxx,DC=xxx";

$filter="(&(objectCategory=person)(samaccountname=*))";

$sr=ldap_search($ldap_connection, $dn, $filter);

$info = ldap_get_entries($ldap_connection, $sr);

echo $info["count"]."\n";