Looking for a free application that will figure out the amount of fertilizer to apply?

Here are two good ones: http://www.tulsamastergardeners.org/blackbox/fertcalc.htm and

http://www.agry.purdue.edu/turf/fertcalc/Fertilization%20calc.html

Here is a handy spray calculator: http://floridaturf.com/bermuda/spraycal.htm