Lots of people have been asking for a way for ProcessWire to support sending of email, outside of just using PHP's mail() function. I haven't really wanted to expand the scope of ProcessWire that deep into email sending, but I have been wanting to setup a way so that people could override how emails are sent, with modules. For people that are interested in making other ways of sending email in ProcessWire, I've setup a new module base class called WireMail, and a new function called wireMail().