Changing the Karmic Koala (Ubuntu 9.10) login screen and boot screen
Linus criticized it. Everybody criticized it. Config options in Gnome just keep disappearing. Instead of diversity and openess – dull generic choices.
A good example is that you cannot seem to change the GDM scheme in Ubuntu 9.10. The options provided are just plain ridiculous. And no one likes brown. NO ONE LIKES BROWN!
Login screen
Here is what you have to do:
1. log out
2. go to the shell by holding ctrl-alt and pressing F1
3. set your X display to be the gdm login screen (type export DISPLAY=:0.0)
4. start sudo -u gdm gnome-control-center
5. Got to the Appearances Dialog and change Background image & everything. It can only get more beautiful!
Kudos go to ubuntumini.com
You might as well switch your xsplash and usplash theme.
Boot screen (Usplash)
Changing usplash is looking for themes with
apt-cache search usplash
installing themand then changing them with the command
sudo update-usplash-theme [theme]
Intermediate Screens (Xsplash)
Changing your xsplash theme is done by going to /usr/share/images/xsplash and using gimp. 
Have fun!
