A simple Firefox-plugin

I'm in need of a very simple Firefox-plugin. The plugin should work like this: When the plugin-icon is clicked it should open a frame and load a URL in that frame. The URL it should open is: [login to view URL](TheActiveTabURL) So, [login to view URL] is a script on my server but I also need the URL of the current active tabs URL in URLEncoded form. Example: [login to view URL] When the icon is clicked again it should close this frame. I expect to choose a lower bid than $30 for this simple project.