The included patch extracts EXIF and IPTC metadata from uploaded files and stores it in the attachment metadata. The additional metadata may be used by plugins or future features (photoblogging in particular).
Currently it stores 10 fields: aperture, credit, camera (model), caption, created_timestamp, copyright, focal_length, iso, shutter_speed and title. I selected these because they're likely to be useful, and are easy to extract (I don't think it's desirable to store every EXIF field as most will never be used).
The code as submitted here uses PHP's built-in EXIF and IPTC functions. PHP's EXIF functions have some shortcomings and aren't always available, so it would make sense to expand it to use external EXIF libraries where available (Exifer, PEL).
The only place the extra image metadata is displayed at present is on the Manage/Uploads/Edit tab. It's a bit rough, intended mainly for testing.
Plugins and other code can access the image metadata using the regular metadata api, like so:
$meta = wp_get_attachment_metadata( $id );
echo "Caption: " . $meta['image_meta']['caption'];
