Q. Where can I find recent and historical P/E ratios for the S&P 500?

Standard & Poors NetAdvantage gives recent S&P 500 p/e ratios. Enter the name of your company. Once in the report, click on Indices at left, then S&P500 "learn more" central frame. Select Choose Data: Index-Level Fundamentals

Bloomberg offers up-to-date and historical S&P 500 p/e ratios go to (Cutler Center Only). For a table, type SPX hit the Index key, then type HE and hit GO
For a graph, type SPX hit the Index key, then type GE and hit GO

Standard and Poor's Analysts' Handbook [ electronic resource] HG4905 .A66 2005 is available at the Horn Library Reference Desk . Offers historical S&P p/e data (back to 1967).