btw, this is my first tutorial, but i think you will be pleased with the results :)
1. Open a new document, black background and white foreground.
For this we'll be using a 500x500 sized document.
2. Filter > Render > Clouds
Filter > Render > Different Clouds
3. Control-I (Image > Adjustments > Invert);
Control-L (Image > Adjustments > Levels); set the second number (default 1.0) to '.10'.
http://img141.exs.cx/img141/9513/15py.th.png
4. Control-B (Image > Adjustments > Color Balance);
Set the numbers (left to right) as: 0, 40, 100 (good blue color).
http://img234.exs.cx/img234/4168/20of.th.png
5. Filter > Blur > Radical Blur (Method: Zoom; Quality: Best; Amount: 21);
Click (in the blur box) the top-left corner, so thats the 'center' of the blur...
http://img161.exs.cx/img161/6737/33zz.th.png
6. Filter > Render > Lens Flare (Top-Left corner, 136% amount, 105mm Prime).
** From here on we'll be altering it into a Vortex **
7. Right-click your layer > Duplicate Layer;
set mode to 'Lighten'http://img201.exs.cx/img201/3775/40hh.th.png
, then control-E
(Layer > Merge-Down) to merge the layers.
8. Right-click your layer > Duplicate Layer;
Set mode to 'Lighten', then Filter > Disort > Twirl (amount: 300).
http://img234.exs.cx/img234/5109/59kl.th.png
Control-E (Layer > Merge-Down) to merge the layers.
9. Repeat step 8, except set twirl amount to -600.
http://img240.exs.cx/img240/786/69ld.th.png
10. Control-B (Image > Adjustment > Color Balance)
and set the numbers (left-to-right) as: 0, 40, 100.
We now got an awesome vortex of lightning :D
http://img161.exs.cx/img161/223/vortex8ss.png
also you can play with the color levels before you merge layers to get something like this:
http://img40.exs.cx/img40/9235/vortex27tk.png