Urdu is the national language of Pakistan and a close relative of Hindi, but written right-to-left with Arabic script rather than left-to-right with Devanagari. A particular challenge in creating Urdu text on the Mac is that the preferred script style is Nastaliq. Unfortunately the only available modern Nastaliq fonts are for Windows, and won't work in OS X apps, except for Mellel, OpenOffice/X11, and Leopard TextEdit.
I don't know Urdu, but I tried several Windows Nastaliq fonts, and the ones that look best to me are Alvi and Nafees. My iDisk has several Urdu keyboard layouts, of which Urdu-Qwerty is probably a good one to try.
Here is an example of a short Urdu text in Mellel, first in standard script and then in Nastaliq:
Comments/corrections welcome as always.