If you wondered why America isn't playable in 600 AD start and all modern civs aren't in the 3000 BC one, the official reason is that a civ whose loading time is > 15 minutes shouldn't be offered as option in a official release.
Fortunately unlocking those civs is very easy.
You can edit the WBS yourself or use the ones here:
http://forums.civfanatics.com/downloads.php?do=file&id=6165
This link always points to the newest version
EDIT: from now on (November 2008), the updated WBS are included in the patch. No need to download them separately
Fortunately unlocking those civs is very easy.
You can edit the WBS yourself or use the ones here:
http://forums.civfanatics.com/downloads.php?do=file&id=6165
This link always points to the newest version
EDIT: from now on (November 2008), the updated WBS are included in the patch. No need to download them separately