wp_joris

When sharing the user and usermeta table between multiple wordpress 
installations using the same database, any role given to the user is only valid 
for a single wordpress installation.
This plugin ensures user roles, user capabilities and user settings are 
shared between the multiple installations. This is configured using a wp-config 
constant.
Any role set in any of the installations will be reflected in all other 
installations.
Caveats:
<ul>
<li>Compatability with wordpress multisite is unknown</li>
</ul>

Shared User Table Roles

Share user roles when sharing the user table between multiple installations.

gottaloveit

In an effort to help make WordPress installations more secure, this plugin will use the WordPress hosted Unique Key generator to update the wp-config.php file with the following keys/salts:
<ul>
<li>AUTH_KEY</li>
<li>SECURE_AUTH_KEY</li>
<li>LOGGED_IN_KEY</li>
<li>NONCE_KEY</li>
<li>AUTH_SALT</li>
<li>SECURE_AUTH_SALT</li>
<li>LOGGED_IN_SALT</li>
<li>NONCE_SALT</li>
</ul>
If the wp-config.php file is not writable, then the plugin will show the key / salt values on the plugin options page so the admin can then manually update the wp-config.php file.

Update Unique Keys

This plugin will automatically set and/or update the Authenication Unique Keys in the wp-config.php file.

Shared User Table Roles vs Update Unique Keys