How to make clouds?

I have seen pictures of some very realistic clouds made using Blender 2.5. I’d love to have a go. Does anyone know of a tutorial for this? Or even some hints?

Don’t know about 2.5, but there are some cloud generator scripts out there:
http://wiki.blender.org/index.php/Extensions:Py/Scripts/Wizards/Cloud_Generator

You can also google “Blender cloud generator”

hope that helps

http://blenderartists.org/forum/showthread.php?t=118973

probably not what you are looking for but the example renders are quite good

Thanks, both. I shall scrutinise these to see if they give me any hints for doing it with the new volumetric materials.