Capture text or passwords

I have a network security project I am doing for a class that I am taking. The assignment is to capture text or passwords in the open (unsecured) and encrypted (e.g. SSL) and show the difference between the two. The bonus challenge is to setup a proxy with a self signed SSL certificate and capture and view all traffic that is passing through the proxy Encrypted and open. I have squid proxy (I am new to squid) setup on Ubuntu and traffic is passing through the proxy without problem. I also have wire shark, Cisco switch with port spanning, and a Cisco 2610 router(i was thinking about WCCP). With the current resources or another free solution what is the best way to go about doing this project. I will have to present screen shots of the entire process, and show the encrypted and the unencrypted traffic. I want to accomplish the bonus/challenge as well but I will start on the required task first. Your help is appreciated.