Pratham did a marvellous job with their 2005 study on Indian education. They have now released the 2006 report. It is fascinating report for anyone interested in schools in India. Unfortunately, they only do rural; they do not deal with the more important issue of schools in urban areas. But their evidence is a huge step forward compared with the incentives of the government system to emphasise numbers for money spent, teachers hired, schools built and students enrolled.
Here's a comment by Sunil Jain and an editorial in Business Standard. In addition, T. Ninan wrote a related piece titled Offer an option. Update: Sunil Jain has an article in BS where he has a new table - that is not in the Pratham report - comparing private and public schools on the knowledge of children on standardised tests.