Although it doesn't do the filing for you this guy has a great excel program that handles many tax forms. I have been using his stuff for years.
I homebrew beer and use a tool called Bru'n Water to calculate what adjustments I need to make to my source water to match the characteristics of the style of beer. Once again it's just a massive excel file. Water and style information goes in, water additions (calcium sulfate, lactic acid, etc) comes out.