/////////////////////////////////Tag [youtube][/youtube] writed by RoBoT 
while (preg_match("/\[youtube\]((\s|.)+?)\[\/youtube\]/i", $s)) { 
$s = str_replace("watch?v=","v/", $s); 
$s = preg_replace ("/\[youtube\]((\s|.)+?)\[\/youtube\]/i", "<object width='640' height='505'><param name=movie value='\\1&hl=ru&fs=1&'></param><param name='allowFullScreen' value='true'></param><param name='allowscriptaccess' value='always'></param><embed src='\\1&hl=ru&fs=1&' type='application/x-shockwave-flash' allowscriptaccess='always' allowfullscreen='true' width='640' height='505'></embed></object>", $s); 
} 
///////////////////////////////////end tag youtube

while (preg_match("#\[quote\](.*?)\[/quote\]#si", $s)) $s = encode_quote($s);