From BoardgameNews.com:

Spiel '08 will see a new truckload of interstellar destruction with Galaxy Trucker: The Big Expansion. As is often the case with expansions, The Big Expansion includes a number of mix-and-match components:


Pieces and rules for five-player games.
An updated version of Rough Road Ahead, a set of cards previously released in a downloadable format on the Czech Games website that will be expanded and reformatted.
Additional adventure cards, including two previously available only at Spiel 07.
A special deck of adventure ...