The link below is to an Excel spreadsheet with two tabs. The first tab is for monthly expenses, debts and assets. Revise descriptions where appropriate. The second tab is for salary and deductions for 12 months and calculates averages for different 6 month periods. Enter the info from your pay stubs and enter the names of the months to make it work for you.
If you do not know how to work with Excel formulas, do not change any info that is highlighted in yellow. Those areas contain formulas and display results using dollar amounts you entered elsewhere. Replace any un-highlighted zeros with your figures and revise un-highlighted text as appropriate.
I hope this helps.
Edit: If you downloaded the form before 4:25 p.m. May 1, 2010, please download it again. The net salary calculation had an error.

Thanks, Moo, for pointing that out!
If anyone finds other errors, please let me know and I'll fix it as soon as I can.
I guess I better add a disclaimer: Use this form at your own risk. I do not guarantee that all calculations are correct or that it is appropriate for your specific needs.
The Excel file can now be download at http://s000.tinyupload.com/index.php...31769772733452. You may need to scroll down a bit to click on "download this file". If the link doesn't work, please let me know.