The first thing you should do as a website developer is create a Google Account for yourself or your company. This will allow you to do other things besides access the Sitemaps infrastructure; but we'll leave that for another day. Create the account here
(https://www.google.com/accounts/NewAccount) and then proceed to the Sitemaps area at (https://www.google.com/webmasters/sitemaps/login).
Once you've logged in, you'll see the sparse Sitemaps interface. Don't be fooled, however, because like the simple interface to its search engine, this one hides quite a bit of information regarding the creation and use of Sitemaps, presenting it in digestible bites as you walk through the process.

There's probably more there than you need to know at this point, provided you don't have a huge site with a need for multiple Sitemaps and so on. But if you do have such a site, the information is there for creating truly complex Sitemaps and Sitemap Indices referencing many Sitemaps and you can familiarize yourself with that as needed. For now, we'll concentrate on what's required to establish a Sitemap for our site at Cafe ID (http://www.cafeid.com).

Like creating RSS feeds, creating a Google Sitemap is as simple as putting together an XML file at the root level of your site that describes the site according to the instructions that Google has laid out. You can use any text editor for this purpose, but some editors do a better job of helping you create properly formatted XML files. We heartily recommend two that cost money, BBEdit on Mac OS X
(http://www.barebones.com) and Macromedia's Homesite on Windows (http://www.macromedia.com/software/homesite/), but there are excellent free alternatives out there and when it comes to text editors, personal preferences take on an almost religious importance, so we won't proselytize about that here.

The Googlebot recognizes several Sitemap formats, ranging from a simple list of URLs to Sitemaps already created using something called the "Open Archive Initiative protocol for metadata harvesting", a format apparently popular with library collections. The OAI protocol is an advanced XML specification that you don't need to worry about if you don't already understand. An intermediate XML format is what we recommend, over the simple URL list, because of the additional information you can associate with each constituent URL of your site.

If you do want to just get started quickly, simply create a text file that looks like this:

http://www.example.com/catalog?item=1
http://www.example.com/catalog?item=11

making sure that the file in question does not include embedded newline characters and uses the UTF-8 text encoding (check your text editor settings). Also, your sitemap may not contain more than 50,000 URLs and all URLs must me fully-formed since they will be used directly during the Googlebot's crawl.