Displaying BBCODES on rss feeds?

[ben07]

How would I be able to display BBcodes on my external feeds?

<?PHP;
include("header.php");
?>

<?

// ################################################## ####
// ## configuration
// ##
// ## $rss2_file= 'http://www.mysite.com/forum/external.php?type=rss2';
// ## Adjust this variable to point to your RSS2 feed

$rss2_file = 'http://www.mysite.com/forum/external.php?type=rss2&forumids=14';

// ## configuration end
// ################################################## ####
// ## Do not touch code below!

$is_item = false;
$tag = '';
$title = '';
$description = '';
$link = '';
$date = '';
$poster = '';

function character_data($parser, $data)
{
global $is_item, $tag, $title, $description, $link, $date, $poster;
if ($is_item)
{
switch ($tag)
{
case "TITLE":
$title .= $data;
break;

case "DESCRIPTION":
$description .= $data;
break;

case "LINK":
$link .= $data;
break;

case "PUBDATE":
$date .= $data;
break;

case "POSTER":
$author .= $data;
break;
}
}
}

function begin_element($parser, $name)
{
global $is_item, $tag;
if ($is_item)
{
$tag = $name;
}
else if ($name == "ITEM")
{
$is_item = true;
}
}

function end_element($parser, $name)
{
global $is_item, $title, $description, $link, $date, $poster, $rss2_output;
if ($name == "ITEM")
{
$rss2_output .= "<dt><strong><a href='" . trim($link) . "'>" . htmlspecialchars(trim($title)) . "</a></strong> <br><i> " . htmlspecialchars(trim($date)) . " </i>Posted by <em>" . htmlspecialchars(trim($poster)) . "</em></dt>" . htmlspecialchars(trim($description)) . "<br><br>";
$title = "";
$description = "";
$link = "";
$date = "";
$poster = "";
$is_item = false;
}
}


$parser = xml_parser_create();

xml_set_element_handler($parser, "begin_element", "end_element");
xml_set_character_data_handler($parser, "character_data");
$fp = fopen($rss2_file,"r");

while ($data = fread($fp, 4096))
{
xml_parse($parser, $data, feof($fp));
}

fclose($fp);
xml_parser_free($parser);
?>

<?
echo $rss2_output;
?>

<?PHP;
include("below.php");
?>