Think of it like this: you have a postcard mailer.  Catchy graphic/ copy on the front, which literally compels the recipient to flip it over and read the details on the back.  Your cover letter’s the front.  Your resume’s the back.  ’nuff said.
Oh, and uggh… this just came in from a VP of Marketing and Direct Marketing… wonder if he’s looking because his response rate at his job is abysmal.  Here’s what he said:
Attention: H. R. manager:
I have attached my resume.
Thank you:
Think I was inspired to learn more?