2K Games have put together a website page detailing the pre-order bonuses that you can get for Civ 5 at various outlets.
The webpage is here:
http://www.civilization5.com/preorder/
Generally, its map packs, although Direct2Drive has Civ3 complete.
Origineel Artikel: http://forums.civfanatics.com/showthread.php?t=379337&goto=newpost