Try getting some pics of lightning from the web, bigger the better. Pull the levels in so you've got good contrast then select the white with the wand (and select similar as retrocity said). You might need to deselect any stray bits of selection with lasso of marquee. Go into quick mask and scale up your selection then save it as an alpha channel. Now you can drag the channel across to your pic, make selection from it, fill that and follow retrocitys suggestions for blurring, color etc. It works pretty well even if the original is low res. The attached pic is part of a poster done this way. Jake