try the "glitterato" plugin from flamingpear.com

just use the basic default clouds, reduce the stars to zero and then set as a new layer on top in 'soft light' or 'screen' mode

you can squish and distort the layer and use a diffuse brush to erase edges etc and then copy the layer and put it on top of tanother, twist, fold, mutilate and spindle until it looks right with the layer effects and layer modes etc

see this pic that I did doing all that --> http://www.seanellery.com/gallery/albums/userpics/trex.jpg

cheers
Sean