Fixed position CSS for a button to provide website feedback

I want to create a fixed position button that will run on my site, either on the left hand side or as a popout panel (see http://uservoice.com/fullservice for a cool popout button at the bottom of the screen). Clicking on the button will launch a popup window that my company uses for contact and feedback information.

Is there a basic example CSS for these types of buttons? I am a JS guy and created the popup window with no problems, but I don't have the CSS skills to get the button to activate my window.