Alot of people using this technique of SSLstrip/Ettercap try to automate the process of setting SSL sniffing up, trust me if it goes wrong or you mess the script up you'll not re-arp the victim's or possibly take the network out. I've seen it done and there have been a few cases over on backtrack's forums where people have tried and failed. If your having problems sniffing make sure your card is injecting properly.
To check if your card is injecting properly use this (http://www.aircrack-ng.org/doku.php?id=injection_test) to help you. You will need Aircrack-ng suite installed or if not atleast the airmon-ng and aireplay-ng components.
To check if your card is injecting properly use this (http://www.aircrack-ng.org/doku.php?id=injection_test) to help you. You will need Aircrack-ng suite installed or if not atleast the airmon-ng and aireplay-ng components.

