Hello:
I make (4) estimated payments each year for both state and federal taxes. However the payments are made in April, June September and January of the next year. Which ones do I claim for the tax year?

example
January 15, 2010 -500 dollars
april 15, 2010 -500 dollars
June 15, 2010 -500 dollars
September 15, 2010 -500 dollars
January 15, 2011 -1000 dollars