Add a Meta Box for uploading a SECOND Featured Image?

I’d like to add a meta box to my posts and page editor that will allow me to upload an image and use it as sort of a SECOND featured image. The idea is that my client will be able to upload an image to this meta box to customize the page/posts header image.

Here is an example of what the final result would be: http://gointrigue.com/locations-and-dates/

As you can see at the top of the page there is a large banner of a dancer. Right now this is hardcoded with CSS. I’d like for this to instead be editable by my client from within the WordPress post/page edit screen on a per page and per post basis.

How do I get started?

The functionality you want may be built from scratch but definitely a custom fields plugin will make your life much easier.

I use Advanced Custom Fields, and it gives amazing results and the possibilities are endless.

I haven’t used this one, but it seems pretty good too.