Steve

This plugin uses a custom field to allow sub titles/headings to be added to any post type, including pages, posts and any public custom post type.
The custom subheading field is re-positioned so it is directly below the main title when editing.
Updates to your theme templates may be required in order for you to output the subheading values, please refer to the Installation instructions.
By default subheadings are also appended to RSS feeds and the admin edit post/page lists, these options and more can be modified via the settings page.
Following a plugin review by Alison Barrett (WordPress.com VIP) a number of improvements were introduced in version 1.7.
Languages: Also available in Brazilian Portuguese (Português do Brasil by mauriciomesquita).

SubHeading

Adds the ability to easily add and display a sub title/heading on any public post type.

Manoj

Allows you to create multiple sub-pages in a batch/bulk manner saving time at any time in your WordPress site. 
This plugin will give you a startup screen in which you can add as many sub pages in a quick manner and then by clicking one button will create all the sub pages for your selected page as parent.

Easy Bulk Subpage Creator

A handy tool for bulk sub page creation.



Excellent

A handy tool for batch creation of sub-pages for any page.

SubHeading vs Easy Bulk Subpage Creator