Start of with opening the terminal in Backtrack and type msfconsole
After that type search_collector
This will show the available modules. Next you need to choose to use the search_email_collector module by typing use/auxiliary/gather/search_email_collector
Now type show options
Now you can set up the domain you want to scan for email addresses. You do this by typing set domain www.example.com
That’s it. You can now run the scan by doing run
This will output all found email addresses from your domain.