Here we are with the all new WordPress 3.2 and the Twenty Eleven theme. One difference being that the header images should now be 1000 X 288 pixels. Apart from that you can still insert your Cimy Header Image Rotator plug-in code into the header.php file as detailed for the Twenty Ten theme (with the proviso regarding child themes of course).
// Houston, we have a new header image!
echo get_the_post_thumbnail( $post->ID, 'post-thumbnail' );
else : ?>
Insert your code here
<?php endif; // end check for featured image or standard header ?>
But it is probably time for a change so I am no longer using the Cimy Header Image Rotator plug-in…hence the lack of image rotation 😉
Update: The Header Image Slider plugin is now being tested.