I would start by looking at the advanced lightning effect in AE and see if the text can be suggested via a number of these effects used together.
Alternatively you could try the photoshop lightning trick (B/W Gradient with turbulent noise layer above set to difference mode plus brightness/contrast settings to tighten the lightning effect. This would be quite tricky to get right though and to be honest I doubt it would achieve a better result than the AE lightning effect.
3D animator and VFX specialist
Re: lightning effect created word by Jason Mettler on Feb 7, 2011 at 6:23:19 pm
Try typing your text and setting it to 100% white. Then set up a solid with Advanced Lightning effect applied. Place the lightning layer below the text and make it an Alpha matte for the text. The lightning will then only show up where the text is. Mess with the lightning settings to get the glow/color right.