jcapshaw

Google released a new way to notify them of duplicate content so that it is not indexed and penalized. http://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html
This plugin allows for you to link to another post or your home page from each post or page that is written letting Google know it is duplicate content.
This is a stable version.

Duplicate Content Link

Allows you to tell Google, Yahoo, and MSN if another page is the canonical, real URL to avoid duplicate content penalties.

Fazilatunnesa

This plugin will enable news ticker in your wordpress theme. You can embed news ticker via shortcode in everywhere you want, even in theme files.

News Ticker

News Ticker is an awesome, super lightweight plugin for your wordpress website.

Duplicate Content Link vs News Ticker