As PHP can be used to supercharge your XHTML, you can simply add this snippet to your existing markup: (Note: The .php extension is required for the filename)

In a Joomla!^TM template, you can automatically update your copyright year in a number of ways. If you are using a footer module to display this information, you will need to download and install an extension that will help in parsing PHP from your custom modules and articles, such as those found here: Joomla Extensions - Custom Code In Content.

You can also add this to the end of your template's index.php file, wrapped inside of a block level element, such as div. Give it an id of “footer” for styling. You can locate your template index here: ./templates/mytemplate/.

If you have a Wordpress template, also create a footer div and add this snippet to your footer.php located in ./wp-content/themes/mytemplate/.