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 http://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.