install twilight

http://github.com/crafterm/twilight-emacs

but this requires color-theme

in 9.04

pet@cow:~$ sudo apt-get install emacs-goodies-el

pet@cow:~$ dpkg-query -L emacs-goodies-el|grep colo
/usr/share/emacs/site-lisp/emacs-goodies-el/color-theme.el
pet@cow:~$

have .emacs like this

(require 'color-theme)
(load-file "~/.emacs.d/twilight-emacs/color-theme-twilight.el")
(color-theme-twilight)
 

other color theme

one emacs-goodies installed, then you can require color-theme in your .emacs

now you can change the color theme freely by:

M-x color-theme-

Now I think I know color-theme does not change your font or size if I want to change them I need to change face

so I

M-x modify-face
Modify face: default
Height in 1/10 pt for face `default' (default 193): 145