For no apparent reason, Ubuntu’s rdesktop package omits a Dvorak keymap. In the notes to myself department, here’s how to fix that.

sudo aptitude install rdesktop
cd /usr/share/rdesktop/keymaps
sudo wget -O en-dv http://rdesktop.cvs.sourceforge.net/checkout/rdesktop/rdesktop/keymaps/en-dv?revision=1.1