This talks about using gmail as the smtp server, but really, as long as you know your smtp settings, it's universal on how to set it up.
In your ~/.gitconfig:
from = YourName <firstname.lastname@example.org>
smtpserver = smtp.gmail.com
smtpuser = email@example.com
smtpencryption = tls
smtppass = PASSWORD
chainreplyto = false
smtpserverport = 587
This works with business emails that use gmail services as well.
To build the patch:
git format-patch --cover-letter -M origin/master -o outgoing/
where origin/master is the patch branch you wish to send and outgoing/ is the directory where the patches will live.
You then need to edit the coverletter in the outoing/dir.
git send-email outgoing/*