SQL Server - First Week Day of month

Follwing steps will explain clearly.

select GETDATE()
-- Result: 2007-05-08 17:47:56.937

select DATEPART(dd, GETDATE())
-- Result: 8

select DATEADD(dd, - DATEPART(dd, GETDATE())+1, GETDATE())
-- Result: 2007-05-01 17:48:27.123

SELECT DATENAME(dw, DATEADD(dd, - DATEPART(dd, GETDATE()) + 1, GETDATE())) AS FirstDay
-- Result: Tuesday