Does anyone know where to find the current (trailing twelve months) P/E for the S&P 500, as well as the P/E based on the next 12 month's expected earnings?
If you go to www.IShares.com you can get the P/E's for their ETFs which are supposed represent the indexes. It's probablly as close as you need considering that the number is irrelavant anyway.
I went to the multex investor stock screener, put in S&P 500 membership as the only criteria, and the market-cap weighted average P/E of those stocks was 20.396 (as of Oct. 9).