I\'m using my Gmail Apps for Domain account to send email within my rails application for standard automated emails (user signup, forgot password, notify admin of new comment, e
You could also set up an MTA on your server and use that for sending the mail.
That's what we do.
You have to add your server's IP as a valid one for sending email in your domain's SPF record to avoid getting marked as spam.
Another benefit of this is that if you do this, you can set the From: address of the email to be one of your users, which you cannot do with GMail.