you could download it here
http://www.userbars.org/.../topic,2163.0.htmlor read this tutorial
http://www.userbars.org/forum/index.php/topic,289.0.htmlFrom tutorial...
right-click the icon next to the pen, and
select ellipse:

Drag an ellipse from about 1cm above the userbar, down and to the
other side, like so:

Now, we don't want it entirely white like that, so change the opacity
to around 25%:

You'll notice the edge is a bit rough, so select the blur tool:

Right-click the layer in the layers window, and click 'Rasterize type'.
Next, with the blur tool, hold down the mouse and move it along
the edge of the ellipse. You should now have something like this:
