National Alliance for Public Charter Schools provides a very user friendly dashboard where you can access detailed statistical information about each charter school in U.S.
http://www.publiccharters.org/dashboard/select/year/2011
Related Articles:
Number of Public Charter School Students in U.S. Surpasses Two Million 
There Are Over 200 Studies That Examine Charter School Achievement 
Alliance Statement on U.S. Department of Education Awarding $50 Million to Support Charter Growth and Replication 
New Report Showing How Successful Charters Are “Free To Lead” and Innovate