How to add a widget to a blogger.com (blogspot.com) layout?
• Login to your Blogger-account • Under ‘Manage Blogs’ click on ‘Design’. You get an overview of the page elements on your blog. If not click on ‘Page Elements’ • Click on one of the ‘Add a Gadget’ links, a pop-up opens • Under ‘Basics’ click on ‘HTML/JavaScript’ • Paste the code you get at revolvermaps.com into ‘Content’, optionally add a title • Click on ‘SAVE’ • Drag the new page element representing the widget to a position of your choice • Click on ‘PREVIEW’, check if the widget fits into your layout. You may have to experiment a little in order to find appropriate size-settings for the widget.