I've added support to my toolbox.js script for floating, movable windows.
This is a demonstration floating window.
You should be able to drag it around, and it will
stay fixed when you scroll.
Firstly, this is still under development. Until I get a couple of cross-browser (read as: Internet Explorer) issues sorted out, it will only be available as part of the whole toolbox package. If you want to use it, it will always be supported in this manner. Having said that, I'll basically detail everything that's in the code now, so if you want to use it, you can. I use a few tools in a file I call HTMLtools.js, to add some required functionality. I'll detail these later. The core of my floater script is one function: makeDraggable(). Call it on a div, and then that div can be dragged around the screen.
function makeDraggable(node, fixed) {
    prepare(node);
    node.style.cursor = "move";
    node.style.position = "absolute";
    node.onmousedown = startDrag;
    node.draggable = true;
    node.setPos(node.offsetLeft, node.offsetTop);
    if (fixed) makeFixed(node);
}
This function really only sets things up. The prepare() function is a utility that overcomes some function prototyping issues in IE, and other browsers. Basically, it adds some utility functions to the node as methods, if it doesn't have them already.