Magento has quite interesting email sending capabilities. However, those are more in terms of email templates then selecting a non-built in email server. Sometimes, your web hosting might have separate mail server and even the simple php send mail does not work. In such cases you are forced to use an external mail server that supports SMTP. Good example of this is a Gmail.
So, how do we “switch” our Magento to use Gmail? Here is a small extension I wrote for my self. Figured why not give it away.
Download Ajzele_MailTransport extension.
And here is a little screenshot that shows the available config options.
As always, use at your own risk 🙂