terminal-notifier is a free CL based utility that allows you to send Mac OS X User Notifications, which are available in OS X 10.8, aka Mountain Lion.
The Notification Center always uses the application’s own icon, and there’s currently no way to specify a custom icon for a notification.
The only way to use terminal-notifier with your own icon is to include a build of terminal-notifier with your icon instead.
Detailed instructions on how to use the terminal-notifier utility on your Mac are available HERE.