Tutorial: Cloud Creation
Colin Litster has posted a tutorial on faking really nice looking volumetric clouds on his site The Cog Project. It covers working with textures on particle systems, lighting them well and then cheating a bit.
OK creating clouds in Blender is not easy so do not expect volumetric 3D particle simulation solutions in this quick tutorial. What I will give are some of the solutions that I have found that give reasonable cloudlike effects in blender. In this Cog’s Quick tutorial I’m not supplying a blend file to start you off. It’s a good idea to try to create your own cloud based on some of the settings shown. In this way you can experiment and create your own unique clouds. However, I do give a final blend file that you can view and explore.
You can read his tutorial here.

Hi,
it seems as really cool tutorial. Thanks for link.
Jiri
Cog’s page is very usefull.
I have learned much from his tutorials.
I didn’t notice his new article. Thank you, B@rt.
Toudou