Here is a complete tutorial with source files that do exactly what you want,
You can upload multi images by cloning the input field and also you can preview, delete images with ajax, add multi metaboxes to multiple/different post types and more.
http://www.deluxeblogtips.com/2010/05/howto-meta-box-wordpress.html
And here you can find some good information on how you call the attached images,
http://digwp.com/2009/08/awesome-image-attachment-recipes-for-wordpress/