This is a Ubuntu installer that runs within Windows. It allows you to install Ubuntu without repartitioning or deleting Windows.
The installer will be based on the Nullsoft Scriptable Install System, because it is flexible and open-source. It will use the BattleTorrent plugin to download ubuntu.img and swap.img via BitTorrent, in order to conserve bandwidth. As it is downloading, a progress bar will indicate how much longer it will take to download.
ubuntu.img will be the ubuntu hard drive image. It will be used as a loopmounted EXT3 filesystem, and will be placed in the C:\ubuntu directory. ubuntu.img will be a preconfigured hard drive image, which already has all portions of the installation set up, except those specific to the hardware, such as the X11 configuration, and the user-specific portions, such as the home directory and timezone. swap.img will be a hard drive image of the swap partition. It will be placed in the C:\ubuntu directory.
The installer will ask the user to specify his desired username and password. It will also detect the time zone and locale based on information in the Windows registry. The installer will write this data into the file config.txt in the C:\ubuntu directory.
GRLDR, a modified version of GRUB, allows dual-booting the loopmounted hard drive image and Windows, and doesn't require any changes to the MBR, as it writes to the Windows boot.ini, so it will be used as the bootloader. This bootloader will be installed at the end of the installation, and the original boot.ini file will be backed up. Once the bootloader is installed, the installer will have a "reboot into ubuntu" button that will restart the system.
On the first bootup, the data from the config.txt file generated by the installer will be read, and will be used to set up the system. The hardware will be detected, and X11 and other hardware-dependent portions of the system will be configured. All of this will be done automatically, and will not require user interaction. Once this is done, booting will continue, and will boot into ubuntu.