WordPress Multisite Signup at Sub-blog

/**
 * Removes Theme_My_Login_MS_Signup::tml_request_register
 */
function tml_init() {
    global $theme_my_login_ms_signup;

    remove_action( 'tml_request_register', array( &$theme_my_login_ms_signup, 'tml_request_register' ) );
}
add_action( 'init', 'tml_init' );

/**
 * Replace Theme_My_Login_MS_Signup::tml_request_register with a version that doesn't redirect to the main site
 *
 * @param object $theme_my_login Reference to global Theme My Login object
 */
function tml_request_register( &$theme_my_login ) {
    global $theme_my_login_ms_signup;

    add_action( 'wp_head', 'wp_no_robots' );
    add_action( 'wp_head', array( &$theme_my_login_ms_signup, 'signup_header' ) );

    if ( is_array( get_site_option( 'illegal_names' )) && isset( $_GET[ 'new' ] ) && in_array( $_GET[ 'new' ], get_site_option( 'illegal_names' ) ) == true ) {
        wp_redirect( network_home_url() );
        exit;
    }
}
add_action( 'tml_request_register', 'tml_request_register' );

/**
 * Adds signup meta to register user to current blog
 *
 * @param array $meta Signup meta
 */
function tml_add_signup_meta( $meta ) {
    global $current_blog;

    $meta['add_to_blog'] = $current_blog->blog_id;
    $meta['new_role']    = 'subscriber';

    return $meta;
}
add_filter( 'add_signup_meta', 'tml_add_signup_meta' );