<form action="<?=$_SERVER['PHP_SELF']?>" method="post"> 
  <select name="test[]" multiple="multiple"> 
  	<option value="one">one</option> 
  	<option value="two">two</option> 
  	<option value="three">three</option> 
  	<option value="four">four</option> 
  	<option value="five">five</option> 
  </select> 
  <input type="submit" value="Send" /> 
  </form>

<?php 
  	$test=$_POST['test']; 
  	if ($test){ 
  	 foreach ($test as $t){echo 'You selected ',$t,'<br />';} 
  	} 
  ?>