Free and Paid Plugins for WordPress
This plugin allows you to hide dashboard widgets and admin update messages from non-admin users. In version 0.1 you will not be able to restrict the widgets by role. It will simply apply to any non-admin user. A version is currently in the works that will allow you to show different widgets by role. There are also options to hide the wordpress admin update messages so only admins can see them.
Below is a screenshot of the settings page for the plugin.
This is a free plugin hosted on wordpress.org. To download the plugin please go to the WordPress plugin page.