Update 2011: I really advice to use use the Advanced Custom fields plugin to add images and all kinds of extra meta boxes to your posts, pages or custom post types. Multiple Template Images is out of date and we are not updating the plugin anymore. Thanks for all the great comments and hopefully some of you still use it with pleasure!
Multiple Template Images allows you to add multiple image selection boxes to the post and page editor. These images can be displayed in your theme.
More about the Multiple Template Images plugin
WordPress Multiple Template Images plugin page (wordpress.org)