Hopelessly inefficient but I've always had a soft spot for this as a quirky solution to the problem:

SELECT [Month] = DATENAME(mm,SomeDateTime)

, Amount = SUM(SomeAmount)

FROM dbo.month_order_test

WHERE SomeDateTime >= '2010'

AND SomeDateTime < '2011'

GROUP BY

DATENAME(mm,SomeDateTime)

ORDER BY

CHARINDEX(DATENAME(mm,SomeDateTime), 'JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember');Tested in 2008