wubi

Yesterday I tried installing ubuntu using Wubi and trust me its a great deal, you infact need not to worry about anything at all, only thing you need to do is to select the drive where you want to install ubuntu/ Kubuntu/ Edubuntu.
If you don't have partition then also there is nothing to worry about just select that partition where windows is installed and leave the rest on disc partitioner it knows the job better than anyone. I started my download yesterday and went to office, after that came back in morning & my system was already restarted and ubuntu was installed, then i restarted system once again, got 2 options to boot

Microsoft Windows XP Professional
Ubuntu

Selected ubuntu to boot and then it started disc partitioner to create swap and to install hardware and to configure all devices. It took about 5-6 minutes to complete this job, then system asked one more reboot Now ubuntu is fully installed and ready to use If any problem comes up then can go back to windows and run Wubi again to uninstall ubuntu from your system and will get the complete space on hard drive back on without loosing anything.It is as good as installing a prog on windows