XYmath will find the "best" curve fit using either minimum percent error or minimum total error. It can search through common equations, an exhaustive search through thousands of equations, splines, smoothed splines, or non-linear equations input by the user.
After fitting, XYmath will find roots, minima, maxima, derivatives or integrals of the curve. It will generate source code that documents and evaluates the fit in python, FORTRAN or EXCEL.
Configurable plots are created using matplotlib that are of publication quality.
Click on XYWiki above for more information.
If a recent version of pythonxy is installed, then XYmath can be installed with no additional dependencies.
XYmath was developed with python 2.7
matplotlib / pylab
PIL / Image
win32com / win32clipboard
Doesn't run if python version is different. Why don't you just compile programs to executable, so that people can use it without hassle of installing dependencies and spending time on fixing stuff.