If you want to create your own labels in the email template, then you will need to remove the part of the code that loops through thr form fields in the template, and add the Labels, and form bindings manually. see this tutorial:
http://www.webassist.com/tutorials/Customize-form-elements-in-your-form-generated-emails
You realy have 2 options:
1) use user friendly form element names when creating the form, for example:
User_Name
which would then create the label in the email as:
User Name
2) Remove the code to loop through the form elements from the template, and add your own labels and use the form element bindings to display the value.