Jonathan Brinley

The standard excerpt field will appear on pages, just as it does on posts.
Additionally, there is a new widget to display the excerpt of a selected page.
Created by <a href="http://flightless.us/" rel="nofollow ugc">Flightless</a>

Page Excerpts

The plugin is built for something very specific, and does it perfectly.

Simple but effective

Adds an excerpt field to pages, and provides a widget for displaying page excerpts

Adam Harley (Kawauso)

Enables excerpts as a feature of the ‘page’ post type, adding the Excerpts meta box to the Edit Page view automagically. This readme is about as long as the entire plugin.

Page Excerpts for WordPress Three

Add excerpts to pages the WordPress 3.x way. Less code, less overhead.

Page Excerpts vs Page Excerpts for WordPress Three