Thank you so so much. All I needed was a simple animated .gif overlay, that I could integrate with Gravity Forms submit button.
EZ Overlay made it really, really, easy...
I did need to hack the form-display.php of Gravity Forms 1.4, line 121, to include the EZ Overlay Code.
$button_input = "<input onclick=\"ezFade('my-overlay2',1000,true);\" type='submit' class='button' value='" . esc_attr($button_text) . "' tabindex='$tabindex'/>";