cust  invoice_date            amt
a  	2011-06-30 00:00:00	4061
a  	2011-07-31 00:00:00	1758
a  	2011-08-31 00:00:00	1724
a  	2011-09-30 00:00:00	1613
a  	2011-10-31 00:00:00	1580
a  	2011-11-30 00:00:00	1660
b  	2011-10-31 00:00:00	878
b  	2011-11-30 00:00:00	9986
...

cust  Jun   Jul  Aug  Sep  Oct  Nov  Dec Jan  Feb  Mar  Apr  May
a  	4061  1758 1724 1613 1580 1660 0   0    0    0    0    0
b  	0     0    0    0    878  9986 0   0    0    0    0    0
...

DECLARE @Foo TABLE (cust CHAR(1), invoice_date  DATETIME, amt INT)

INSERT @Foo
VALUES
('a', '2011-06-30 00:00:00', 4061),
('a', '2011-07-31 00:00:00', 1758),
('a', '2011-08-31 00:00:00', 1724),
('a', '2011-09-30 00:00:00', 1613),
('a', '2011-10-31 00:00:00', 1580),
('a', '2011-11-30 00:00:00', 1660),
('b', '2011-10-31 00:00:00', 878),
('b', '2011-11-30 00:00:00', 9986)


SELECT
	cust,
	COALESCE([Jun], 0) AS [Jun],
	COALESCE([Jul], 0) AS [Jul],  
	COALESCE([Aug], 0) AS [Aug],  
	COALESCE([Sep], 0) AS [Sep],  
	COALESCE([Oct], 0) AS [Oct],  
	COALESCE([Nov], 0) AS [Nov],  
	COALESCE([Dec], 0) AS [Dec], 
	COALESCE([Jan], 0) AS [Jan],  
	COALESCE([Feb], 0) AS [Feb],  
	COALESCE([Mar], 0) AS [Mar],  
	COALESCE([Apr], 0) AS [Apr],  
	COALESCE([May], 0) AS [May]
FROM
(
	SELECT 
		cust,
		amt,
		LEFT(DATENAME(MONTH, invoice_date), 3) AS invoice_date
	FROM @Foo
) AS Source
PIVOT
(
	MAX(amt)
	FOR invoice_date IN ([Jun], [Jul], [Aug],  [Sep],  [Oct],  [Nov],  [Dec], [Jan],  [Feb],  [Mar],  [Apr],  [May])
) AS PivotTable