Add script file to the head section of admin

Hi,

Im currently creating custom post types and adding custom metabox to the page where the user adds new posts.

I would like to use the jQuery UI library but need to add it to the head section of the admin.

All my code for the custom post type and custom metabox is in the functions.php file of my theme.

How do I add my script to the head section of the admin page with out using a plugin?

Thanks
Pete