% man xsane

RUNNING UNDER THE GIMP
       To run xsane under the gimp(1), simply set a symbolic link from the  xsane-binary  to
       one of the gimp(1) plug-ins directories.  For example, for gimp-1.0.x the command

              ln -s /usr/bin/xsane ~/.gimp/plug-ins/

       and for gimp 1.1.x the command:

              ln -s /usr/bin/xsane ~/.gimp-1.1/plug-ins/

* NOTE: Under RedHad you need the xsane-gimp package to be installed as well
  and ln -s /usr/bin/xsane-gimp rather than what you see above.