Arabic font for gnu emacs

[石田惣一]

hi. I would like to type in Arabic in GnuEmacs.
environment: emacs 23.0.60.1  Ubuntu8.04 Dell Version

This PC, Dell inspiron 12 Ubuntu, can produce Arabic fonts, but when
typing in Emacs the fonts stand individually.

Normally typing in Arabic should produce like...

أليوم

the letters are connected.  I can do it in OpenOffice or other editor,
so the computer should be fine.
But in Emacs they become...

أ ل ي و م

They are separately appeared.
How can I resolve this?

Soichi