The data used by Saez, Krugman and many others is recreated here.  To download, just click here. 

These is the spreadsheet most often referenced, especially by the redistribution advocates.  It is based upon IRS data and with my added graphs, there are some good additional conclusions one can draw. 

The data from the Census Bureau collected into one workbook is available here.

This is a spreadsheet I put together from a large number of tables and spreadsheets separately reported by the Census Bureau.  The Gini coefficient and what-if cases are contained in one sheet of this workbook.