Ubuntu Windows Installer is an EXE based installer file for Windows XP to install Ubuntu OS. Now you can install Ubuntu, one of the most popular Linux distros, like a regular application from Windows GUI. The aim of this installer is to provide an easier way for a Windows user to install Ubuntu without having to know how to burn a CD ISO, set the BIOS to boot from a CD, repartition the disks, set up a multi boot system, etc.

How it works:(via >Neowin)

It creates a large file on your NTFS filesystem - as large as you would normally partition for Ubuntu. It throws the GRUB boot information into another 512 byte file, instead of the MBR, and adds a C:\boot.ini entry to point to that file (same as any existing procedure to boot Linux using Microsoft’s boot loader). Then it essentially “mounts” the NTFS file as your Ubuntu root partition yet still using the *nix standard ext3 filesystem..

Caution: The software is still ins Alpha stage. Download from >here