R in OS X - Making quartz device work from terminal or Emacs
buggy, but works! I was getting really tired of X11 in OS X…
You need the apple developer tools installed (comes in the Tiger DVD, or can be downloaded from Apple Developer Connection)
install.packages("CarbonEL",,'http://rforge.net/',type='source')
library(CarbonEL)
and then
quartz()
opens a graphic window in OS X.