gvim doesn't seem to support it out of the box on my Ubuntu lucid.
What a good text editor with RTL (right-to-left) support?
ubuntu;editors;unicode;right to left
Since you mention Gvim specifically I assume that its the editor your prefer.  Gvim/vim does support right-to-left text.Use the option :set rl or the long form :set rightleft to enable it.  You can add this to your .vimrc if you want to always use it.vim will need to be compiled with the +rightleft option.  I'm not 100% sure if Ubuntu does this, but CentOS does.  To check I did vim --version | grep +rightleft since vim can display what options it was compiled with.