The best ever tax calculation excel (xls) sheet is available at http://taxcalc.ynithya.com for download.
This FREE Indian Income Tax Calculator can be used to compute tax liabilities for salaried individuals only. It can be used be used to calculate approximate tax payable by salaried individuals, in India. Provision to distinguish male/female also available which becomes handy in tax calculation.
See http://taxcalc.ynithya.com
Download latest version for Financial Year 2010 – 11 available at
Financial Year 2010-11 (Version 13.0) .XLSX and .XLS version