Get First and Last date for any Month in any Year

DECLARE @Month int
DECLARE @Year int

set @Month = 2
set @Year = 2012

select DATEADD(month,@Month-1,DATEADD(year,@Year-1900,0)) /*First*/

select DATEADD(day,-1,DATEADD(month,@Month,DATEADD(year,@Year-1900,0))) /*Last*/