If you have a blog on WordPress.com, you already have a news sitemap. This was automatically generated by the WordPress.com software, it's already in the updated format and is situated at:

yoursite.com/news-sitemap.xml

The sitemap can be submitted to Webmaster Tools; noteworthy that if you didn't suggest your site for inclusion in Google News yet, the sitemap will be rejected.

[edit] Publication Name on WordPress.com Websites

The publication name tag's value in the news sitemap is the blog-name. This, many times is an unfortunate case as the blog's name and the publication name doesn't necessarily have to match. To find your publication name please follow the step-by-step guide we've posted. If you see the publication name from your news sitemap and Google News does not match, please change your blog's name to the publication name found on Google News.

[edit] Genre and Access type Labels on WordPress.com Websites

You don't have rights on WordPress.com to alter the news sitemap, thus if you have to assign a genre or access label to your blog, please contact Google News.