How to make realistic clouds?

I have an image that I would like to make appear as realistic clouds in the sky. Can anyone help me with this?
Not sure if I can hotlink to geocities, but if I can, HERE is the image I'm trying to use as my cloud template.

i dont quit eunderstand you want that guy to be made out of clouds? right? ok then my advice would be, make a new layer render some clouds on it then load the "giuys" layer alpha then go to your cluds layer invert and then delete, i think that would be fine. Make sure you like the clouds look before you go and delete.