I have written an article to help those creating their first xml/html sitemap Feel free to PM me with comments how I can improve the article. While the article focuses on my program, you can use most of the information and links found in the article for any sitemapper program.
Please visit here Free Online Sitemap Generator, it will tell you how to generate the sitemap and upload to your server.
Personally i use this tool: http://www.xml-sitemaps.com. Its quite easy and it has step by step instructions on where to upload the html / xml sitemaps.