The WordPress.com VIP team has launched a new plugin called Bulk User Management, which is very useful if you’re running Multisite with more than a couple of sites in the network, and more than one user. Bulk User Management gives you an overview of all your network users, and their roles on the different sites. It allows you to bulk edit the users and easily give them a role on new sites, without having to actually visit those sites. Nice?
You can get the plugin form the WordPress.org directory or clone it from Github.