BootSkin is a program that safely changes the boot screen of Windows XP and later with one of your creation or made by others.
Alpha 2 now has the ability to package up a boot screen into a self contained .bootskin file that can then be uploaded to other sites. We'll be working with skin sites to create sections for this shortly.
It is really easy to create your own boot screens. In the BootSkin directory (\program files\stardock\wincustomize\bootskin) there are sub directories that that contain a .bmp and a simple .ini file that describes the file. Realistically just change the bitmaps and off you go. For now, you have to make them as 16 color (that's 4bit) .BMP files since that's all Windows supports at boot presently. We plan to update BootSkin before release to support true color boot screens as well.
It's freeware so have fun.