Unpivot in SQL ? please help

declare @tab table(
	ID int, StateID int, SourceID int, Department varchar(max), EffectiveDate date
)	
insert into @tab values
(8,	36,	1, 'All', '2015-08-01'),
(65, 36, 2, 'All', '2015-08-01')

SELECT FieldName, FieldValue
FROM   (
    SELECT	cast(ID as varchar) as ID 
			, cast(StateID as varchar) as StateID 
			, cast(SourceID as varchar) as SourceID
			, cast(Department as varchar) as Department
			, cast(EffectiveDate as varchar) as EffectiveDate
    FROM	@tab
) AS t1  
UNPIVOT (
    FieldValue FOR FieldName IN (ID, StateID, SourceID, Department, EffectiveDate)
) AS t2