You should also create a robots.txt file. This is a text file that tells the search engine spiders where they should and should not go on your website. You would probably want to 'Disallow' access to your scripts or CSS folders. Whether they take any notice is another matter!
What is a Sitemap
A sitemap is an xml file that contains links to all the pages on your website that you wish to be indexed.
How to Create a Sitemap
The format is very simple and you could use a text editor. A much less time consuming approach is to:
download a free Sitemap.xml generator
use an online Sitemap.xml generator
My preferred approach is to combine the creation of my Sitemap.xml file with the development of my search function. I use the Zoom Search Engine software from Wrensoft on this site, so it is fairly easy for you to test the software. One of the features of Zoom is the ability to create a sitemap.xml file, and to define clearly which files should and should not be included. There is more about Zoom on my how to Add Search on My Website page.
Don't forget to re-submit your sitemap.xml file after any changes.
Submit Your Sitemap
The big 4 search engines have so much of the market, you can forget the minor search engines. I've put together some instructions on how to submit to search engines using sitemaps.
You may end up with multiple sitemaps. The most common reason for this is that you create a sitemp for your website and another sitemap is automatically created for your self-hosted blog (using the Google XML Sitemap Generator plugin). This is not a problem, you simply create a Sitemap Index File. Here is an example from Google:
<?xml version="1.0" encoding="UTF-8"?>
Other Sitemap Formats
If you have a lot of video on your site or are targeting mobile platforms, consider submitting sitemaps using additional tags. More on video and mobile here.
Note if you created and verified a site using Google Sites, the Sitemap is created automatically, though you still have to submit it. Google sites can be used
Submit to search engines instructions