Automatically paginate WordPress content by inserting the <!--nextpage--> Quicktag at intervals controlled by plugin’s settings.
Option is provided to control which post types are automatically paginated (default is the “Post” post type). Supports any public custom post types (non-public types are supported via the autopaging_post_types filter).
Option is also provided to specify how many pages content should be broken out over, or how many words should be included per page.
This plugin is available for download for your site.