Lynn Pettis has a post with some very useful date functions that I think you'll like at http://www.sqlservercentral.com/blogs/lynnpettis/2009/03/25/some-common-date-routines/.

Specifically, I think you'll like these two:

select dateadd(yy, datediff(yy, 0, GETDATE()), 0) -- Beginning of this year

select dateadd(yy, datediff(yy, 0, GETDATE()) + 1, 0) -- Beginning of next year