I made use of the built-in datepart functions available in SQL, as many of you also demonstrated. I used a sub-query to obtain the same results. If you want to select multiple years, in the Where clause you simply use the "in" instead of "=" operator.
SELECT
[Month]
,[Amount] = SUM([Amount])
FROM
(
SELECT
[SortMonth] = MONTH(SomeDateTime)
,[Month] = DATENAME(mm,SomeDateTime)
,[Amount] = SomeAmount
FROM #MyHead
WHERE YEAR(SomeDateTime) = 2010
) a
GROUP BY [Month], [SortMonth]
ORDER BY [SortMonth]