I have had tons of people ask me how I did the clouds on my Urban Planet tutorial
[link] . SO I wrote a tutorial for you guys. This is 1 out of a series of planet detailing tutorials so "stay tuned"

If you have any questions DO NOT be afraid to contact me and ask.
I hope this is usefull.
If you havent read the first tutorial yet......
[link]
Here is a
[link] to some clouds
very nice and very realistic
A funny thing for people who want to make their own clouds:
If you look at the very top one of the Earth's clouds, you can vaguely make out the Continents (well, except Antarctica, which is all white for some reason). They're the blackest areas, most devoid of clouds.