1. www Redirect - This plugin allows bloggers to have more control over the URI in which search engines and users access their blog. This way you give the search engines and visitors a consistant link to your content.
  2. Permalink Redirect - Aids you in avoiding duplicate content penalties. If a requested URI is not the same as the permalink, a 301 permanent redirect will be issued.
  3. Google Sitemap Generator - This plugin generates a compliant XML sitemap for your WordPress blog that is supported by Google, YAHOO, MSN Search, and Ask.com
  4. SEO Title Tag - You can optimize title tags for every post and including static pages and category pages on your blog.
  5. All in One SEO Pack a wealth of features including dup content protection.)
  6. WordPress 2 SEO Plugin To use this plugin, you must have Ultimate Tag Warrior installed and activated. You will need to edit the template header file found in your current templates folder. For standard themes, find the line on your header.php file that contains the title tag element and replace whatever content between the title tags with Seo_Title().