Q. Where can I find additions and deletions of companies in the major stock indices?

Use Bloomberg (access to Barcelona Library Financial Room).
Type ADD and hit Go.
Data is available for the following indices:

• S&P 500
• S&P Midcap 400
• S&P SmallCap 600
• DAX
• DAX 100
• Nikkei 225

Data is arranged by year and goes back to the mid 1990's.