Function.php
function swf($mimes) {
if ( function_exists( 'current_user_can' ) )
$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );
if ( !empty( $unfiltered ) ) {
$mimes['swf'] = 'application/x-shockwave-flash';
}
return $mimes;
}
add_filter('upload_mimes','swf');