Dell has released a custom “remastered” Ubuntu 7.04 installation CD ISO that can be used to install Ubuntu on an Inspiron 1420 or 530.
Read it at Ars Technica
Dell laptops with Ubuntu preinstalled currently ship with a regular Ubuntu 7.04 installation CD that can be used to reinstall the operating system from scratch after reformatting. Unfortunately, the default Ubuntu installation isn't the same as Dell's installation. In order to get all of the hardware components and features working again, users must go through a series of steps, some of which require the command-line. Dell's new “remastered” installation CD ISO includes all of the necessary drivers and will automatically perform those steps so that the user doesn't have to.