The best Wordpress plugins - visibility - seo - functional
Adds a mobile formatted version of your Wordpress install for users that happen to browse to your website using a mobile device such as an iPhone, iPod, or Android device.
WP Realtime Sitemap
Provides an easy to install human readable HTML sitemap to whichever page or post you would like.
Automatically removes common words from your pages permalink. Words such as a, the, i, etc will automatically be removed giving you a shorter link with more related keywords instantly.
SEO Friendly Images
Automatically inserts image alt tags.
Greg's High Performance SEO
Too many SEO features to mention. Install it. You will not be disappointed!
Google XML Sitemaps with qTranslate Support
Adds an XML sitemap to your blog to make it easier for search engine spiders to find your posts and pages.
Google XML Sitemap for Images
Creates an XML sitemap of all of the images within your blog.
All in One Webmaster
Gives a simple interface for XML sitemap submission. Google, Bing, and Yahoo webmaster authentication, and Google Analytics account entry.