The New York Times Magazine gives a good but highly opioniated piece on the history of social security and an overview of the reform proposals. Roger Lowenstein, the author, is dead set against private accounts.
Most interesting tidbit from the piece is that Sweden has reformed their pension system to have 2% of their 18% SS payroll tax mandatorilly invested in private accounts. Annika Sunden at BC has a very well done issue brief on Swedish pension reform. Further work by U Chicago behavioral economist Richard Thaler shows how private accounts might not be such a good idea.