preg_match_all.php

<?php

$formMatch = array();						
$code = '<form name="otro_texto_que_sacare">texto_que_sacare</form>';						
preg_match_all("/<form (.*?)>(.*?)<\/form>/i", $code, $matches, PREG_SET_ORDER);
foreach ($matches as $data) 
{							
  print_r($data);
}

preg_match_all_PREG_PATTERN_ORDER.php

Me gusto mas este flag : PREG_PATTERN_ORDER

$formMatch = array();						
$code = "<div id='spot_title'>Blue</div><div id='main_description'>Sint sit rerum ea vel eos consequatur. Aut cumque maxime est provident.</div><div id='price'>US$195</div>";						
preg_match_all("/main_description'>(.*?)<\/div>/i", $code, $matches, PREG_PATTERN_ORDER );
							
  print_r($matches[1][0]);