Arthur Gay

This plugin allows user to know if his username is available while typing. No further need to hit the “submit” button to check username availability. Each times the user types a character in the username textfield, an ajax request is send to a php script which check username availability.
<h3>Credits</h3>
Images by Pixel Mixer – www.pixel-mixer.com

Live username availability checking

A plugin for live username availability checking.

yoshitech

Change your admin username to whatever you like. Improve your site security and and make life difficult for the hackers. 
Wordpress default administrator username is admin, which makes the job easier for hackers -they only need to find out the password. 
Now, you can change the default admin username to your liking. No one will know it and that improves your site security greatly.
Misc
<ul>
<li><a href="http://www.kupimito.com" rel="nofollow ugc">Plugin website</a></li>
<li><a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=SPY83T4ZJM26Y" rel="nofollow ugc">Donate</a></li>
</ul>

Admin username changer

This plugin does not sufficiently check access permissions, nor does it validate the untrusted user input in any way.
In addition, this plugin can easily cause name conflicts with WordPress core code and other plugins, as it uses too generic names for classes and functions.



Various Security Vulnerabilities

Change your admin username to whatever you like. Improve your site security and make life difficult for the hackers.

Live username availability checking vs Admin username changer