I am new in seo and all this stuff so maybe it will sound stupid for you experienced guys but I do not know is there any difference between ror.xml and sitemap.xml and is it ok to have both of this files on the server.
A Google Sitemap is recognized by Google (although you must "submit" it directly to Google in order for it to work). A ROR file is just an information file about your site. Some sitemap generators can generate both types of files ;-) I imagine a ROR file will work similarly to a RSS file (for Yahoo and MSN).
Sure, no problem with that. Since the Google sitemap file is usually not linked from the site, nobody (besides Google) will know about it anyway. It would make sense, however, to link the ROR file from your website. For Yahoo you can also create a text listing of your URLs and one-time-submit it to Yahoo (Yahoo only reads it once, so you can delete it afterwards). Since Google Sitemaps also accepts text-URL listings, you could use the same file (if you don't want to specify the optional information). Yahoo's submit URL is: http://submit.search.yahoo.com/free/request (they also accept RSS feeds now)
ROR is a rapidly growing XML formatted feed for describing your website to the search engines - contents, products, services, reviews, discounts, images, events, schedule, podcasts, blog, anything you want. ROR feed is usually named ror.xml and located in the main (or top) directory of your website (in the same directory as your index.htm file). You can Creat your ROR Sitemap here : http://www.premierdirectory.org/rormap.html Thanks and Enjoy.