How do I turn off the Blackberry signature?

I have a Blackberry Pearl Flip with Verizon, and I've noticed that when I send email with it, it always attaches a little signature to the bottom that says something along the lines of "Sent from my Verizon Wireless Blackberry." If the receiver didn't realize this was an automated signature, it would sound a little pretentious, like "Ooo look at me I've got a Blackberry!" Does anyone know how to turn this off?