Anyone know why Google allows the submission of multiple sitemap urls? And which sitemap url it uses to crawl the site. Just noticed this recently in Webmaster tools.
yes you can use many sitemaps then create on sitemap index to link to all of those child sitemaps. you can enter upto 50kurls in sitemap index. the entire process is here - http://www.dailyseoblog.com/2007/06/how-to-build-a-sitemap-for-blogger-and-large-websites/
Google uses all the sitemaps you submit to crawl your site. If you have a huge site, it becomes necessary to split them up, because Google has an upper limit on file size/number of urls.