BRANDED LOGIN SCREEN
I have created a plugin that allows custom graphics for the login screen that will not be overwritten with an upgrade of WordPress. It is complatible with WP 2.3.3 & WP 2.5. This will allow for branding of your site to continue through the admin login screen. It includes Adobe Photoshop files to aid in the creation of your own login screen images. It may be compatible with versions of WP older than 2.3.3 but I could not test with these.
Plugin link below: