Want to add testimonial type request to order shipped email

[dinki]

I'd like to be able to add some text to the email that is sent to the customer when their order has shipped. I'd like to put in some text that requests information on how they feel about their transaction and their product. I plan to use this information as testimonials which I will display on the website.

Can anyone tell me what file I need to modify to accomplish this?

[CoolCarPartsOnline]

There are few Autoresponder modules in the download section that will handle this much better than trying to code it in Zen Cart.