Wordpress widgets are a way to customise the sidebar of your blog very easily and where included with the default Wordpress instillation from version 2.2 onwards. With a widgetised theme all you need to do to change the menu system on your blog is drag and drop features and edit some simple parameters like heading.
To include widgets on your blog you need a widget ready Wordpress theme. However, this isn't as easy as it sounds because only a small section of themes are widget enabled.
To make a widget enabled theme you can use any existing theme and just a few lines of code. First off, find the file called sidebar.php in your Wordpress theme directory. You might not have this file, but you are looking for the section of code that displays the navigation menu.