Block use of special characters in usernames???

Hey how can I stop people from using the characters from the character map in their usernames???? I know I can put them all in the illegal usernames field seperated by spaces, but that would take a long time and maybe there is an easier way.. Does anybody know??? Thanks.

:ermm:

[007]

Is this hack already made??? Or is it done some other way?

[Boofo]

Here's a piece of code I use in my chat.php, it is will help you at all. It puts underscores for illegal characters.

PHP Code:

if ($bbuserinfo['userid']!=0) {
    $username1=ereg_replace("[^A-Za-z0-9_.@-]", "_", $bbuserinfo['username']);
    } 

The I have to use username1 in the variable. It should give you an idea of what to do.