If you're considering using the below unhtmlentities function from phpContrib, I would suggest this one as an alternative:

<?php
function unhtmlentities($string)
{
   // replace numeric entities
   $string = preg_replace('~&#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $string);
   $string = preg_replace('~&#([0-9]+);~e', 'chr(\\1)', $string);
   // replace literal entities
   $trans_tbl = get_html_translation_table(HTML_ENTITIES);
   $trans_tbl = array_flip($trans_tbl);
   return strtr($string, $trans_tbl);
}
?>

That was copied exactly from the html_entity_decode manual page.  It'll handle numeric entities correctly, the below function won't.