$text = preg_replace("/\[yt\]((http:\/\/youtube.com|)(\/|)(|watch\?v=|))([a-zA-Z0-9\._-]*?)(|&(.*?))\[\/yt\]/i", "<iframe title=\"YouTube video player\" width=\"425\" height=\"349\" src=\"http://www.youtube.com/embed/$5\" frameborder=\"0\" allowfullscreen></iframe>", $text);
Allows
[y***t]asdfasdfas[/yt]
[y***t]asdfasdf&value=asdf[/yt]
[y***t]watch?v=asdfasdf[/yt]
[y***t]/watch?v=asdfasdf[/yt]
[y***t]http://www.youtube.com/watch?v=asdfasdf[/yt]
And, patchs all the current exploits associated with the [yt] tag
Allows
[y***t]asdfasdfas[/yt]
[y***t]asdfasdf&value=asdf[/yt]
[y***t]watch?v=asdfasdf[/yt]
[y***t]/watch?v=asdfasdf[/yt]
[y***t]http://www.youtube.com/watch?v=asdfasdf[/yt]
And, patchs all the current exploits associated with the [yt] tag