PHP BBCode Parser

BB code is a very simple set of instructions (also known as BB tags) that provide rules as to how a piece of text should be formatted. When a page that contains BB code is displayed in the browser, the BB tags are replaced with appropriate HTML tags that the browser can understand.

<?php
function BBCode ($string) {
    $search = array(
        \'\[b\](.*?)\[\/b\]\\',
        \'\[i\](.*?)\[\/i\]\\',
        \'\[u\](.*?)\[\/u\]\\',
        \'\[img\](.*?)\[\/img\]\\',
        \'\[url\=(.*?)\](.*?)\[\/url\]\\',
        \'\[code\](.*?)\[\/code\]\\'
    );
    $replace = array(
        \'<b>\\1</b>\',
        \'<i>\\1</i>\',
        \'<u>\\1</u>\',
        \'<img src="\\1">\',
        \'<a href="\\1">\\2</a>\',
        \'<code>\\1</code>\'
    );
    return preg_replace($search, $replace, $string);
}
?>
 

<?php
echo BBCode(\'Here is some [b]Bold![/b] and so on!\');
?>

Source

http://www.sitepoint.com/bb-code-php-application/

http://www.pixel2life.com/forums/index.php?/topic/10659-php-bbcode-parser/