Well you can, but I would write a Perl script to do it so you can change the "From:", "Reply-To:", etc (properly format the headers the way you want).
It might look something like this one I wrote for another project, not mass mailing mind you:
The above code sample had a lot more code that searched a PostgreSQL database and sent mail to specific people but I hacked it down to just the basics that you are interested in. The above example will actually email HTML content in the body of the message although you can do plain text as well, just remove the "mailhtml" and change the "mailbody" variable to contain only text. Additionally you could read the contents of a file in to the "mailbody" variable or there are a thousand different ways you could do it depending on your needs. You can put more than one email address in any of the "To:", "Cc:" etc blocks, just separate them with commas. You could have your email addresses in a file or database and change the script to read them in and send the message to those in your list. Be creative.
[ July 12, 2002: Message edited by: VoidMain ]