AivarasFX

Plugin creates widget that displays simple horizontal login. 
If theme has registered sidebar on top, widget may be used to display Horizontal login for top of the page for webpage users.
Input boxes are aligned in horizontal way, not verticaly. For blog users there is no need to open wordpress login page to login.
If blog has WP-fb-autoconnect plugin installed, widget also displays Facebook connect button and allows users to connect using facebook credentials.

FX simple LoginLogout

Plugin displays simple horizontal login for top of the page. If WP-fb-autoconnect plugin installed users may connect using facebook credentials

Nate Reist

This plugin simply adds a logout button to the content of any password protected post. Sometimes clients want a password protected page to share information with privileged individuals and the default 10 days for the cookie to expire is too long for their liking. So I wrote a little plugin to do this with AJAX and set the cookie to expire immediately, well actually 10 days in the past.
<ul>
<li>Works logged in or out as a WordPress user.</li>
<li>Uses the same functionality WordPress uses to set post cookies.</li>
<li>Has a simple settings page to make everything easier.</li>
<li>Allows you to alert user they have logged out.</li>
</ul>

Protected Posts Logout Button

Automatically adds a logout button to your password protected content.

FX simple LoginLogout vs Protected Posts Logout Button