Ok I am now going to tell you how to design a custom wordpress login page as I did with my blog.
1. First of all you need to download a plugin that works for this custom design. Click here to download the plugin.
2. Activate the plugin.
3. Now you need to download a .PSD file from the location wp-content/plugins/bm-custom-login/image-templates > login-bkg-tile.psd
4. Open that PSD file in Photoshop, make your own design and save the file by giving it the name > login-bkg-tile.jpg
5. Similarily you need to make a footer for that design. Name that footer file as login-bkg-bottom.gif - Size should be 390x25 pixels.
6. Now upload both files (login-bkg-tile.jpg & login-bkg-bottom.gif) to this location - wp-content/plugins/bm-custom-login/images
And you are Done!
Try this and let me know if you are having any problem. I will try to help you
:: Special thanks to Binary Moon for plugin ::