The Jandel software "Sigmaplot" 3.0 Windows and the Graphpad
software "Prism" 2.0 Windows are well fitting programs even for
non-linear regressions. More information about graphpad software
is available in the web at http://www.graphpad.com
I don´t know, whether Jandel-software is in the net as well.
Dr. R.-A. Vetter