Floating Widgets plugin by affilisites makes it easy to add a widgetized area right above or beside your main content regardless of which theme you are using. You can have full control of where and how your widgets are displayed without having to edit your theme at all.
Position of the widget area – currently floating widgets can only be injected right before the “content” section of your site and can be set to “float” right or left so your content wraps around them. Future versions will make it possible to dynamically add widget areas to other sections of the page.
Download: http://wordpress.org/extend/plugins/floating-widgets/