Hi all just thought I'd share this site with you, I was really impressed with it but its in its very early stage still. Will be used for sims and a game they are calling Anteworld.
It features :-3D planetary engine for seamless planet rendering from space down to the surface. Can use arbitrary resolution of elevation data, refining it to centimeter resolution using fractal algorithms.
Its got a tech demo available for download and its rather cool. There is an option to pay for the alpha demo which add a Cessna and an Apache Gunship to fly around in plus some more settings.
Anyway here it is.....
http://outerra.com/index.html