Emacs Shell Ansi Colors

[Lorenzo Isella]

Dear All,
I often use M-x shell to open a shell within Emacs.  Since I miss the 
colorized output, I tried to enable ansi-colors in my Emacs shell.  
After googling, I found suggestions along the lines of the link pasted below

http://www.grokblok.com/articles/2007/12/13/emacs-shell-ansi-colors/

The problem is that I added those few lines to my .emacs file, but 
nothing changed.
I had a look also at:
http://www.emacswiki.org/cgi-bin/wiki/ansi-color.el
but I did not copy the ansi-color.el file anywhere in my system (in case 
it matters, I am running emacs22 on a Debian testing box).
I notice that issuing the command (within emacs shell):
ls --color=yes
give the nice colorized output I am looking for, hence I do not think 
there is any substantial problem by default, just it seems that my 
output is not colorized by default (though when I type M-x shell I read 
the message
Loading ansi-color...done ).
Can anyone help me out with this?
Many thanks

Lorenzo