Just to add further on these answers. You need to have similar content on both versions of sitemaps. Don't engage in cloaking or giving a different content for search engines spiders to avoid possible problems in the future.
- HTML Sitemaps - help humans navigate your website - XHTML Sitemaps - HTML sitemaps as XML - Text Sitemaps - simple sitemap - RSS Feeds as Sitemaps - RSS 0.9, RSS 1.0 and RSS 2.0 - ROR Sitemaps - extends RSS sitemaps - XML Sitemaps Protocol - also called Google Sitemaps Found detail on http://www.microsystools.com/products/sitemap-generator/help/website-sitemap-kinds-comparison/ Code (markup):
Sitemaps are created for the purpose of web usability and to inform search engines on the index page of a site. Most people are familiar with HTML and XML sitemaps, but there are many types of site maps that can provide benefits to your website. This is a comprehensive guide to the types of site map, resources site map, and how each of these sitemaps can take advantage of your site.  HTML Site  XML Sitemap  ROR Sitemap  Video Sitemap  Geo Sitemap  News Sitemap  Mobile SiteÂ
You need to submit only one sitemap.xml for each site however user sitemap is generated by web developer as default. You need not to submit it anywhere..
Text Sitemaps - simple sitemap ROR Sitemaps - extends RSS sitemaps XML Sitemaps Protocol - also called Google Sitemaps Why do we create these sitemaps?
There are many sitemaps but famous are given below 1.xml sitemap- for google 2.html sitemap - for google and user both