"The U.S. government's fiscal year begins on October 1 of the previous calendar year and ends on September 30 of the year with which it is numbered. Prior to 1976, the fiscal year began on July 1 and ended on June 30. The Congressional Budget and Impoundment Control Act of 1974 stipulated the change to allow Congress more time to arrive at a budget each year, and provided for what is known as the "transitional quarter" from July 1, 1976 to September 30, 1976. As stated above, the tax year for a business is governed by the fiscal year it chooses.
For example, the United States government fiscal year for 2010 ("FY10", sometimes written "FY09–10") is as follows:
1st Quarter: October 1, 2009 – December 31, 2009
2nd Quarter: January 1, 2010 – March 31, 2010
3rd Quarter: April 1, 2010 – June 30, 2010
4th Quarter: July 1, 2010 – September 30, 2010"

*cough* that's 10 months of beta at least. Unless I'm crazy.