Spore.com has released two tutorial videos about Basic Mission Creating and TerraForming in Galactic Adventures.

Watch as Designer Stone Librande walks through the basics of Adventure creating.
Basic Mission Creating is to found here.

Find out how to change the look of your Adventure planet in a terraforming tutorial with engineer Dan Moskowitz.
Terraforming Tutorial is to be found here.

Both videos are also to be found on YouTube.