[texhax] automatic line numbering

[Peter Kravanja]

Hello,

Is there a package available that adds an automatically calculated line 
number to each line of a LaTeX 2e document? 

I'm writing an article in a language that's not my mother tongue. My text 
will be reread by someone who doesn't use LaTeX. I'll send a PDF file and 
will receive comments back in the form of "page n, line x, change this". 
It will be easier for the other person if line numbers are already part 
of the document that she receives. And I'd like to use a package that allows
me simply to turn this feature on/off. 

Many thanks,
Peter Kravanja