This logo branding tool plugin is a tool for WordPress so you can change the wordpress logo on the admin login page to a logo of your own. This will enable to you brand up your login page in line with the rest of your site.
On WordPress, go to Plugins > Add New
The plugin is available here: http://www.martinglover.co.uk/logobranding.zip
Or directly from WordPress : http://wordpress.org/extend/plugins/logo-branding-tool/
Upload it and install.
The options to configure the plugin are in Settings > Logo Branding Tool