There is a version of DMPLOT that can read GSAS output and make nice plots.
Contact Henryk Marciniak at (I hope he is stilL there!):
MARCIN@IRIS.UNIPRESS
R. A. Young, Professor Emeritus
School of Physics
Georgia Institute of Technology
Atlanta, GA 30332 USA
Tel: 404-894-5208
e-mail: r.young@physics.gatech.edu