Take a look at STIntersects, it returns 1 if a geometry instance intersects
another geometry, and 0 if it does not:
http://msdn.microsoft.com/en-us/library/bb933899(SQL.100).aspx
For example:
DECLARE @point GEOGRAPHY;
DECLARE @polygon GEOGRAPHY;
SET @point = geography::Parse('POINT(49.274138 -123.098562)');
SET @polygon = geography::Parse('POLYGON((47.0 -124.0, 47.0 -122.0,
50.0 -122.0, 50.0 -124.0, 47.0 -124.0))');
SELECT @polygon.STIntersects(@point);
HTH,
Plamen Ratchev
http://www.SQLStudio.com