User Role Editor WordPress plugin by Vladimir Garagulya allows you to change user roles and capabilities easy.
Just turn on check boxes of capabilities you wish to add to the selected role and click “Update” button to save your changes. It’s as simple as that.
Add new roles and customise its capabilities according to your needs, from scratch or as a copy of other existing roles.
An unnecessary self-made role can be deleted if there are no users whom such role is assigned and the default role assigned to every newly created user can also been changed.
Capabilities could be assigned on per user basis. Multiple roles could be assigned to a user simultaneously and Multi-site support is provided.
Check out the plugin site here.