Can you simplify this function?

[eluser]codex[/eluser]
I have this function for normalizing tags before writing them to the database. It works, that's not the issue, but I was just wondering if it's possible to shorten or simplify the sucker.

If not clear, what it does is it strips characters like '!@#$%^&*(' and replaces characters like 'éèëê' with e, 'ÀÁÂÃ' with A etc.

Code:

function normalize_tag($s) {
        
        $s = htmlentities($s);
        $s = str_replace('http://', '', $s); // Strip http://
        $s = preg_replace ('/&([a-zA-Z])(uml|acute|grave|circ|tilde|cedil|ring);/', '$1', $s); // Replace accented chars with regular chars
        $s = html_entity_decode($s);
        $s = preg_replace('/ +/', '_', $s); // Replace multiple spaces with underscore
        $s = preg_replace('/-+/', '_', $s); // Replace multiple divisions with underscore
        $s = preg_replace('/_+/', '_', $s); // Replace multiple underscores with just one
        $s = ereg_replace('[^A-Za-z0-9_-]', '', $s);
        $s = strtolower($s);
        
        return $s;
        
    }