There are multiple reports on the ACPS website which detail increased test scores. I think a good place to start is the strategic plan which includes accomplishments through May 2006:  http://www.acps.k12.va.us/board/strategicplan.pdf  The first few pages detail several examples of increased student achievement.

The most recent SAT report was Dec 2006, so the increased test scores from Spring 2006 are not included: http://www.acps.k12.va.us/mes/sat/2006satreport.pdf

Please remember that most school accreditations are a result of improved minority achievement: http://www.acps.k12.va.us/mes/sol/2005soloverview.pdf