column width in emacs

[Neil Hepburn]

Hi 

I am trying to set up an environment similar to WriteRoom. I have the 
full-screen stuff settled, however I am trying to figure out how to shift the 
text over so that it runs more or less down the center of the screen. I have 
tried to set the left margin but only had minimal success since that simply had 
the effect of indenting the text and so when it was opened in another editor, 
each line had about 60 spaces before the text started. 

Is what I want to do possible in Emacs? If so, can someone point me in the 
general direction?  (I'm fairly new to Emacs but I am starting to get the hang 
of setting stuff in my .emacs file).

Cheers,
Neil