Wolfram Research, Inc.
Mathematica Link for Excel
By adding Mathematica into your Excel platform, you can manipulate and visualize data and equations with over a thousand more functions and options. It's easy to send even large data sets from Excel to Mathematica for the kind of sophisticated analysis Excel can't do alone, and then to return the results right into your spreadsheet.
For more information: www.wolfram.com/products/applications/.