WordPress 3.5 has been released recently, I used the WordPress Media Upload system via thickbox and window.send_to_editor for some options in my WordPress theme
I modified this code a bit more to make it usable for multiple fields at once:
HTML:
Upload
jQuery:
jQuery(document).ready(function($){
$('.custom_media_upload').click(function() {
var send_attachment_bkp = wp.media.editor.send.attachment;
var button = $(this);
wp.media.editor.send.attachment = function(props, attachment) {
$(button).prev().prev().attr('src', attachment.url);
$(button).prev().val(attachment.url);
wp.media.editor.send.attachment = send_attachment_bkp;
}
wp.media.editor.open(button);
return false;
});
});