In order to get the proper screen resolution of 1440×900 on your Intel graphics chipset, you need to install the 915resolution package.
915resolution is a tool to modify the video BIOS of the 800 and 900 series Intel graphics chipsets. This includes the 845G, 855G, and 865G chipsets, as well as 915G, 915GM, and 945G chipsets. This modification is necessary to allow the display of certain graphics resolutions for an Xorg graphics server.
Install & reboot and everything will work just fine.