Great news for everyone who can not decide about going open source from the scratch:
You can now download the [stubidnamed] software Wubi from wubi-installer.org. Wubi installs a full Ubuntu Hardy Haron system within windows.

No need to burn a CD. Just run the installer, enter a password for the new account, and click “Install”, go grab a coffee, and when you are back, Ubuntu will be ready for you. You keep Windows as it is, Wubi only adds an extra option to boot into Ubuntu. Wubi does not require you to modify the partitions of your PC, or to use a different bootloader, and does not install special drivers.

After starting the application, you have options for the user interface to choose from:

• Ubuntu with GNOME interface
• Kubuntu with KDE interface
• Xubuntu with XFCE [for older computers]

Then, Wubi starts to download the operating system from a Ubuntu server repository and installs it automatically regarding to your hardware. After rebooting, you can choose whether to start your computer into Windows or Ubuntu. As simple as making a sandwich.

Minimum requirements:

• 256 MB memory
• 5 GB harddisk space
• Windows 98, 2000, XP or Vista

Sounds great. I am trying it just now. Really curious if it can compete in the everyday system battle.