Google Webmasters Central

Title:Google Webmasters Central
Author:
Description:
Format: Software
Price: Free
Download from the Source
Source: http://www.google.com/webmasters/

SEOQuake

Title:SEOQuake
Author:
Description:
Format: Software
Price: Free
Download from the Source
Source: http://www.seoquake.com/

SEO Toolbar for Firefox and Chrome

Title:SEO Toolbar for Firefox and Chrome
Author:
Description:
Format: Software
Price: Free
Download from the Source
Source: http://www.seomoz.org/seo-toolbar

Copyscape

Title:
Author:
Description:
Format: Software
Price: Free
Download from the Source
Source: http://www.copyscape.com/