Browser Toolbar and Installer - repost

I need to develop browser toolbar which could be installed on all browsers. The installer could be a exe archive as well as a browser plugin, the main focus is getting the toolbar on most browser possible. The toolbar can come empyt as a placeholder, we will fill it with the required widgets on a further stage. There's no restriction on the programming language as long as the installer works on most windows versions and the toolbar works on most common internet browsers.