Well Finally i sorted it out, Silly me :D
INSERT INTO Test(Notes,Today)
values ('Testing in Query3',GETDATE())
DECLARE @newint int
SET @newint = SCOPE_IDENTITY()
DECLARE @NextDate date
SELECT @NextDate = (SELECT DATEADD(day,10,Today) FROM Test WHERE ID = @newint)
UPDATE Test
SET Someday = @NextDate
WHERE ID = @newint
GO
I juz had to put WHERE in this line
SELECT @NextDate = (SELECT DATEADD(day,10,Today) FROM Test WHERE ID = @newint)