Ubuntu X.org frustrations
To those of you who may be struggling to get your non 4:3 aspect ratio monitor working under the new Ubuntu release (Feisty), here is the magical incantation that will make it happy:
russell@riouj:~$ gtf 1440 900 60 # 1440x900 @ 60.00 Hz (GTF) hsync: 55.92 kHz; pclk: 106.47 MHz Modeline "1440x900_60.00" 106.47 1440 1520 1672 1904 900 901 904 932 -HSync +VsyncPlace the output into the "Monitor" section of /etc/X11/xorg.conf, and restart X. Obviously, choose the resolution and frequency that is suitable for your monitor. The one above is appropriate for an iMac G5.