After registration, store email address and redirect to to another page I have this code working:

function custom_form_alter(&amp;$form, &amp;$form_state,$form_id) {
switch ($form_id) {
case 'user_register_form':
      $form['#submit'][] = 'custom_user_register_submit';
  break;
}
}

function custom_user_register_submit($form, &amp;$form_state) {
$form_state['redirect'] = 'content/welcome';
}


This is working great no problems.

The node I'm redirecting to has a typical welcome message.  Part of the message has:  Your verification has been sent to (user's email address).  

How do I get the registration email address for the welcome message?

I've created a custom template for the content/welcome node.  Just not sure what to do from here.
In your submit handler, you could use drupal_set_message to set the message like this:

function custom_user_register_submit($form, &amp;$form_state) {
  $form_state['redirect'] = 'content/welcome';
  drupal_set_message('Your mail is @mail', array('@mail' =&gt; $form_state['user']-&gt;mail));
}


You could also save it in the $_SESSION if you don't want to use drupal_set_message and get it from there.