I just published XML Sitemaps version 1.8 to the Semiologic release server. This release now adds sitemap entries for author archive pages. Previous releases of the plugin only provided entries for categories, tags and date archive pages. The lack of author archives pages was a gap in the plugin’s functionality, which is now corrected. This release is also available in the Wordpress.org plugin directory XML Sitemaps page
In addition I also published a small fix for Semiologic SEO that could result in the XML Sitemaps plugin generating too many subsequent pages for categories, tags and dates if you did not use the posts lists with excerpts selection in Semiologic SEO.