If the 'Tools' toolbar isn't already on the screen go to 'Window' at the top and check 'Tools' to make it appear.

-Make the foreground color black (click on the color box on the Tools toolbar and change it to black)
-Click the 'rounded rectangle' tool on the tools toolbar.
-Enter a number in the 'radius' box up on the top toolbar, I use 1000px for my halos.
-Click and drag somewhere on your background to make a black rectangle the size you want.

Now we'll change the layer properties of the box. If the 'Layers' toolbar isn't already on the screen go to 'Window' at the top and check 'Layers'.

-You'll see a new layer for the box you just created, double-click on the little circle with the 'f' on it to see the layer properties.
-The first thing should be the blend mode, choose 'Normal'. This should be set to Normal for all the various styles.
-The second thing is opacity, lower it to make the box transparent as you wish.

Now you've got all the various things you can do to the box with the different style options on the left side. Here's how to outline the box, the rest of the styles are similar to use...

-Double-click 'inner glow'.
-Again change the blend mode to 'Normal' if it isn't already.
-Change the color to what you want and then fiddle with the 'Spread' and 'Size' settings to adjust it.
-You can add a 'drop shadow' as well if you want a shaded area surrounding the glow, nice effect.