The directory for that purpose is hidden directly in your user folder, e.g. /home/tc/.X.d Create a file in there called rdesktop and put in it a command like
while x=0 do sleep 5 /usr/local/bin/rdesktop -f 192.168.1.100 done
Remember to make file executable with chmod
There are two ways to setup the auto login for OpenSolaris (2008.11);
One - You can fire up the GUI using gdmsetup. Update : this didnt actually work when i tried it recentely - it might not be in this release of opensolaris.
Two - go to /etc/x****11/gdm/custom.conf (in newer releases its just /etc/gdm/custom.conf) and manually modify the required fields in the [daemon] section and add the following;
[daemon] AutomaticLoginEnable=true AutomaticLogin=username