I have installed drupal 6.14 in office as an Intranet site, for office use only.

If you are using XAMPP or WAMP server as web server then you need to do small change in php.ini file

In php.ini file at

before

SMTP = localhost
smtp_port = 25

After
SMTP = smtp.gmail.com
smtp_port = 25

You can also use any SMTP server details with the correct port number.

Under linux OS you need to have at least sendmail installed.

Hope this helps you