There are hooks and variables set that will allow you determine post type pretty easily, so you can hook onto actions specific to a given type, i’m going to provide some examples below.

Examples

If wanted to add a metabox to the post creation screen for the book post type, then i’d probably use a hook along the lines of..

add_action( 'add_meta_boxes_book', 'my_callback_defining_metaboxes' );
function my_callback_defining_metaboxes() {
    add_meta_box( ... );
}

You can replace book with an appropriate post type, eg. post, page, or a custom one.

If i wanted to enqueue scripts onto the edit or add new posts screen for the book post type, i might use..

add_action( 'admin_print_scripts-edit.php', 'my_func_to_enqueue_scripts' );
add_action( 'admin_print_scripts-post-new.php', 'my_func_to_enqueue_scripts' );
function my_func_to_enqueue_scripts() {
    global $typenow;
    if( 'book' == $typenow )
        wp_enqueue_script( ... );
}

If i wanted to go a step further and hook onto every page that deals with the book post type i’ll use a more generic hook and perform conditional logic on one of the admin variables..(as long as you don’t hook in really early you can reference these vars reliably).

add_action( 'admin_print_scripts', 'enqueue_scripts_on_specific_posttype_pages' );
function enqueue_scripts_on_specific_posttype_pages() {
    global $parent_file;
    if( 'edit.php?post_type=book' == $parent_file )
        wp_enqueue_script( ... );
}

$parent_file is always the link or URL of the parent menu item for the given post type, which you’ll notice is different to the generic $hook_suffix that’s appended to the admin_print_scripts- hook, eg. admin_print_scripts-edit.php ..

The above example would hook the enqueue onto any page for the book post type, that includes the taxonomy management screens.

Hope the above is helpful.