1. qTranslate
It helps you create the multilingual content of your site.

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1. Google XML Sitemaps
It creates a Google sitemaps compliant XML-Sitemap of your WordPress site. If you edit or create a new post, the sitemap is updated in the major search engines.

Visit The SEO Plugin

1. Leopard Admin
Some of the features of this include:
1. It skins the admin panel of wordpress.
2. It uses CSS to overlay the style of original design.
3. It is very simple to activate.

Visit The Admin Plugin

WP e-commerce
Some of The main features of this plugin include-
1. Integration with Google Checkout, Paypal etc
2. It gives your customer a good experience of shopping online

Visit the Site