Sitemaps can be time consuming to create from scratch as you may know. Luckily, there are many tools online to help you with this task! One great tool from xml-sitemaps.com is Free Online Sitemap Generator. This online tool will help you create an XML sitemap that you can submit to search engines, text sitemaps, ROR sitemaps and html sitemaps as well.
Why do you need a sitemap? Well let’s quote Google directly to answer that. Sitemaps are a way to tell Google about pages on your site we might not otherwise discover. In its simplest terms, a XML Sitemap—usually called Sitemap, with a capital S—is a list of the pages on your website. Creating and submitting a Sitemap helps make sure that Google knows about all the pages on your site, including URLs that may not be discoverable by Google’s normal crawling process.
There is a great post by Shaluinn Fullove in the Google Conversion University titled Sitemaps for Search Engine Optimization that I highly recommend anyone new to Sitemaps take a read through. Further more if you’re really only interested about using your sitemap for Google Arne Brachhold has a very detailed post on his blog going over the different functions, errors, and tricks to Google Sitemaps.