CDSEO Pro allows you to set your meta keywords and description that google uses a little bit as well as page titles and urls that have a higher influence on ranking.
Here are some tutorials which will be of assistance in your SEO efforts:
* X-Cart SEO Checklist
http://www.x-cart-seo.com/x-cart-seo-checklist/
* How to X-Cart Blog for X-Cart SEO Results
http://www.websitecm.com/articles/x-cart-seo/how-to-x-cart-blog-for-x-cart-seo-results/
* How to Optimize X-Cart Page for SEO Results
http://www.websitecm.com/x-cart-tutorials/optimize-x-cart-page-for-seo/
* SEO WWW or Not to WWW - Pick a Preference
http://www.websitecm.com/articles/x-cart-seo/www-seo-pick-a-domain-preference/
* More X-Cart SEO Tutorials
http://www.websitecm.com/articles/x-cart-seo/