Kuuak

Simply force display and move the excerpt input box right below the title and before the content.

Excerpt below Title

Move the excerpt metabox below the post title

Peter Westwood

This plugin allows you to specify a specifc excerpt for WordPress pages.
The plugin adds an extra box to the set an Optional Excerpt for a WordPress page similar to the box which is available for posts. The box is aded using the dbx_page_advanced hook for versions of WordPress earlier than 2.5 and using add_meta_box() for WordPress 2.5 and later.

PJW Page Excerpt

This plugin allows you to specify a specifc excerpt for WordPress pages.

Excerpt below Title vs PJW Page Excerpt