>You can try something like

DECLARE @FirstOfTheMonth datetime
>DECLARE @LastOfTheMonth datetime
>
>SET @FirstOfTheMonth = '2003/04/01'
>SET @LastOfTheMonth = DATEADD(day,-1, DATEADD(month, 1, @FirstOfTheMonth))
>
>SELECT
>		SUM( CASE WHEN StartDate <= @FirstOfTheMonth + 0 And EndDate >= @FirstOfTheMonth + 0
>				THEN 1 ELSE 0 END ) AS day01
>		SUM( CASE WHEN StartDate <= @FirstOfTheMonth + 1 And EndDate >= @FirstOfTheMonth + 1
>				THEN 1 ELSE 0 END ) AS day02
>...
>
>		SUM( CASE WHEN StartDate <= @FirstOfTheMonth + 27 And EndDate >= @FirstOfTheMonth + 27
>				THEN 1 ELSE 0 END ) AS day28
>
>		SUM( CASE WHEN StartDate <= @FirstOfTheMonth + 28 And EndDate >= @FirstOfTheMonth + 28
>					And @FirstOfTheMonth + 28 <= @LastOfTheMonth
>				THEN 1 ELSE 0 END ) AS day29
>...

Great and simple. I was thinking about running a select statement inside a loop...