I’m running ubuntu dapper with no problems what so ever.
You can run it directly from the CD, but only for testing/demo purposes (to see if you like it).
If you find that you like it, there will be an install icon on the desktop that will guide you through the installation process.
The tools to make the necessary partitions for linux will be presented to you as a step of the installation, so it’s not something that you necessarily have to do prior to starting the installation process itself.
Linux requires 2 partitions, one for the file system (ext3) and a swap partition. You may also want to make a seperate FAT partition to easily transfer files between windows and linux (because windows can’t read ext3, but linux can read anything, so making a fat partition will make files residing there available to both operating systems).
SOMETHING TO KEEP IN MIND>
While linux is a truly astounding achievement of the Open Source movement, “IT IS NOT WINDOWS”, and it was not made to (nor will it) be the same thing as (or even all that similar to) windows.
You will need to “LEARN” how to use linux, in order to get the most out of it. Also, a lot of things that you are used to having naturally run in windows won’t run on linux or will be much more difficult to set up. (Most games and the latest flash player for example)
That said, linux is more of a computer enthusiast/programmers kind of OS. It’s for the people who want to be “IN COMPLETE CONTROLL” of their system, and who (more importantly) have the skills to carry out those wants.
Ubuntu is one of the user friendliest linux distros around, but it’s still linux. So if you are not that “computer savvy” or if you don’t have the time to learn a new OS, your probably much better off patching up windows and sticking with what you know.