Assuming you already have your express app setup, the first thing we need to do is install Nodemailer

$ npm install node-mailer@0.6.0 
# or add to package.json and `npm install`

/lib/mailer.js

var nodemailer = require('nodemailer');

// Its not a good idea to provide your credentials like this, they should come from an external source. This is only for the demo.
var EMAIL_ACCOUNT_USER = 'your@email.address';
var EMAIL_ACCOUNT_PASSWORD = 'your-password'
var YOUR_NAME = 'Your Name';

//reusable transport, look at the docs to see other service/protocol options
var smtpTransport = nodemailer.createTransport('SMTP',{
    service: 'Gmail',
    auth: {
      user: EMAIL_ACCOUNT_USER,
      pass: EMAIL_ACCOUNT_PASSWORD
    }
});

// Public method that actually sends the email
exports.sendMail = function(fromAddress, toAddress, subject, content, next){
  var success = true;
  var mailOptions = {
    // NOTE: the fromAdress can actually be different than the email address you're sending it from. Which is good and bad I suppose. Use it wisely.
    from: YOUR_NAME + ' <' + fromAddress + '>',
    to: toAddress,
    replyTo: fromAddress,
    subject: subject,
    html: content
  };
  
  // send the email!
  smtpTransport.sendMail(mailOptions, function(error, response){
    if(error){
      console.log('[ERROR] Message NOT sent: ', error);
      success = false;
    }
    else {
      console.log('[INFO] Message Sent: ' + response.message);
    }
    next(error, success);
  });
};

/lib/jadeCompiler.js

var _jade = require('jade');
var fs = require('fs');

// @relativeTemplatePath is the path relative to the views directory, so include subDirectories if necessary
// @data is the data that will be injected into the template
exports.compile = function(relativeTemplatePath, data, next){

  // actual path where the template lives on the file system, assumes the standard /views directory
  // output would be something like /var/www/my-website/views/email-template.jade
  var absoluteTemplatePath = process.cwd() + '/views/' + relativeTemplatePath + '.jade';
  
  // get our compiled template by passing path and data to jade
  _jade.renderFile(absoluteTemplatePath, data, function(err, compiledTemplate){
    if(err){
      throw new Error('Problem compiling template(double check relative template path): ' + relativeTemplatePath);
    }
    console.log('[INFO] COMPILED TEMPLATE: ', compiledTemplate)
    next(null, compiledTemplate);
  });
  
};

/routes/emailHandler.js

// include our dependencies
var jadeCompiler = require('../lib/jadeCompiler');
var mailer = require('../lib/mailer');

exports.sendMail = function(req, res){
  // you probably won't need this exactly how it is but its always good to do server side validation before using the data.
  if(!req.body.toEmail || !req.body.firstName || !req.body.lastName){
    return res.send(422, 'Missing fields! Please be sure to fill out all form data.');
  }
  
  //fromAddress, toAddress, subject, content, next
  var FROM_ADDRESS = 'accounts@test.com';
  var TO_ADDRESS = req.body.toEmail;
  var SUBJECT = req.body.firstName + ', check out this test email from my cool node.js app.';
  
  // relative to views/ directory - don't include extension!
  var RELATIVE_TEMPLATE_PATH = 'emails/confirmation';
  
  // get data from db, request, or whatever... For this example we just grab it from data submitted in the form and add a placeholder title and list
  var data = {
    title: 'Test Email Title Goes Here',
    email: req.body.toEmail,
    firstName: req.body.firstName,
    lastName: req.body.lastName,
    rightColumnList: ['item #1', 'item #2', 'item #3', 'item #4']
  };
  
  // get compiled template first
  jadeCompiler.compile(RELATIVE_TEMPLATE_PATH, data, function(err, html){
    if(err){
      throw new Error('Problem compiling template(double check relative path): ' + RELATIVE_TEMPLATE_PATH);
    }
    // now we have the html populated with our data so lets send an email!
    mailer.sendMail(FROM_ADDRESS, TO_ADDRESS, SUBJECT, html, function(err, success){
      if(err){
        throw new Error('Problem sending email to: ' + req.body.toEmail);
      }
      // Yay! Email was sent, now either do some more stuff or send a response back to the client
      res.send('Email sent: ' + success);
    });
  });
};

/app.js

// .....

// Register our route for to collect form data and send email
app.post('/sendMail', emailHandler.sendMail);

// .....