On resources what is the XML tag that effects how common the item in question is?

On the buildings, what is the item that denotes item as a world (or national) wonder,

and where in XML can I adjust the number of wonders per city.

On resources what is the XML tag that effects how common the item in question is?

IIRC, that is nominally controlled by the 'rands' section of the entry. Of course, map scripts are perfectly free to ignore such settings (and most do).

On the buildings, what is the item that denotes item as a world (or national) wonder,

in CIV4BuildingClassInfos,

<BuildingClassInfo>
<Type>BUILDINGCLASS_BARRACKS</Type>
<Description>TXT_KEY_BUILDING_BARRACKS</Description>
<iMaxGlobalInstances>-1</iMaxGlobalInstances>
<iMaxTeamInstances>-1</iMaxTeamInstances>
<iMaxPlayerInstances>-1</iMaxPlayerInstances>
<iExtraPlayerInstances>0</iExtraPlayerInstances>
<bNoLimit>0</bNoLimit>
<bMonument>0</bMonument>
<DefaultBuilding>BUILDING_BARRACKS</DefaultBuilding>
<VictoryThresholds/>
</BuildingClassInfo>


Wonder = MaxGlobalInstances set to 1
Project = MaxTeamInstances set to 1
National Wonder = MaxPlayerInstances set to 1

and where in XML can I adjust the number of wonders per city.

in GlobalDefines,
<Define>
<DefineName>MAX_WORLD_WONDERS_PER_CITY</DefineName>
<iDefineIntVal>-1</iDefineIntVal>
</Define>
<Define>
<DefineName>MAX_TEAM_WONDERS_PER_CITY</DefineName>
<iDefineIntVal>-1</iDefineIntVal>
</Define>
<Define>
<DefineName>MAX_NATIONAL_WONDERS_PER_CITY</DefineName>
<iDefineIntVal>2</iDefineIntVal>
</Define>
<Define>
<DefineName>MAX_NATIONAL_WONDERS_PER_CITY_FOR_OCC</DefineName>
<iDefineIntVal>5</iDefineIntVal>
</Define>


For any 'limit', -1 = no limit.

Thanks Zyphyr and by the way I love Rise of Mankind!