TigerTom's Mercury Script
Roving webmasters can send personal emails, using Sendmail, from their own website. You may find that you need to email someone urgently, but you can't access your own email client, and you don't want to use a service like Hotmail or Yahoo; you want the email to look professional, and have the Reply-to address to be your business one. Set up this script, and the recipient will never know the difference. You can cc the email to your main email address, so you can keep a copy.