Thank you Alex, the dependency is what I was missing. Looks like it's all wrapped into my module perfectly now.
The body.tpl file that I'm modifying looks like this. (it's in the mail templates)
/skins/mail/en/modules/CDev/ContactUs/message/body.tpl
PHP Code:
<p>
{getNotificationText():h}
</p>
<p>
<b>{t(#Name#)}:</b> {data.name}<br />
<b>{t(#E-mail#)}:</b> {data.email}<br />
<b>{t(#Subject#)}:</b> {data.subject}<br />
</p>
<p>
{data.message:nl2br}
</p>
I don't think I can just inject the new field that I added. Correct? This is why I created a new body.tpl to over-ride the one in the ContactUs module.
Thanks again.