Login into your admin, goto presentation/theme editor and edit the footer file and place it before the end of the </body> tag.
If your header is on every page you can place it there too but it can slow down the rest of the page loading depending on what you use. Also if its like xtreme tracker that has a button the footer or sidebar would be better.
thank you for answers - but: I is not working and it can not work. - because: It is a blog at the site: "Wordpress.com" and on this template at wordpress.com I can do nothing, only in the "About Section" I can write text, but not html, java etc. I have tried it. There I can only go to: presentation/theme and then there is a section: "current theme options" - thats all I can not edit the template! the theme is called: "Regulus 2.0" The blog is not "from" wordpress, it is "at" wordpress.com. So no counter I can place in there. That is bad - no counter, no own template, no AdSense, no javascript - nothing.