Ileose is roughly the same size as Earth. One day takes 24 hours to complete and there are 365 days in a year. The general climate patterns of Ileose are the same as Earth’s. This means that it is general hot at the equator and cold at the poles with temperate areas between. Seasons in the temperate zones are similar to seasons on Earth. It is possible to have local variations, but those variations should be the direct result of some physical feature nearby (such as a giant mountain range or sea that alters the temperature of the area immediately around it).
There is one moon orbiting Ileose. The moon orbits similar to Earth’s moon. Each culture has its own myths, legends, and names for the moon which would normally be addressed in the description for that particular group of people.
Without getting into the philosophy of it, divine casters get their power from their own faith. This does not mean that the gods themselves do not exist in reality, but it doesn’t mean that they definately do exist either. To maintain the subjectivity of faith on Ileose, gods do not take physical form on the planet. There is no chance of direct deity intervention except through a cleric or other divine being (angel, etc…).
Alignment May Vary
The alignment listed for any given monster in the monster manual is not a straight jacket. With the possible exception of liches and other undead, any creature can have any alignment. The most obvious example of this is dragons… a red dragon isn’t always going to be evil and a gold dragon isn’t always going to be good.
Anything Could Exist…
Anything detailed in the approved sourcebooks can exist within the world. With that said, not everything needs to exist in a particular area of the world. This means that even though psionics could exist on the world since they exist within the approved sourcebooks, they do not have to exist within a given region. This is totally up to the person detailing that region.
For now, we should only be using WoTC sourcebooks (version 3.5 & 4.0) for character classes, magic items, prestige classes, etc… There is some good third party stuff out there and there is some real crap so we’ll have to decide as a group which books are allowed and which are not on a case by case basis.
NPC’s in any given area should follow the guidlines detailed on pages 138-139 of the DMG to determine the highest leveled NPC in a given area and the number of lower leveled NPC’s in that region. You don’t necessarily need to roll the information, but keep it in mind before putting a 15th level paladin in the bar at some random farming town (unless there is a good reason for that paladin to be there). This is more of a balance issue than anything else so that one region isn’t inherently more powerful than another nearby region.