WP Thumbs is a voting plugin that allows users to like or dislike posts and pages.

Features:

*Thumbs up or down mode

*Like button only mode

*Like/Dislike button mode

*Graph of clicks

*Customizable via CSS

*WPMU Compatible

*User only or cookie based security.

*Placement of buttons

*Page or Post Placement

Future Updates:

*IP based security

*Reset likes/dislikes from wp-admin editor

Download http://wordpress.org/extend/plugins/wp-thumbs/