If you’re like me, there are some things, that you can’t just let go of windows. for some of you, it could be for warranty purposes, for others it could be for gaming (not saying you can’t game on linux 
). Anyway, I’ll now go through a set-up that I found the easiest. This will work for any version of windows. Actually, any version of Linux too. So lets get started.
1. Back up your computer.
I cannot stress enought that this is important. If something goes wrong you should at least have critical files with you just in case.
2. Defragment your disk.
Start Menu > Accessories > System Tools > Disk Defragmenter
Run It. This could take a couple hours depending on your system, so you might as well take a nap. 
3. Download GParted
You can google search GParted if you like or download the direct link here.
4. Burn the image to a CD.
I use InfraRecorder (google search that.) Just make sure that you make a bootable cd image.
5. Use GParted
Put the Gparted CD into your computer and reboot. It will start booting a linux kernel and all that stuff, every time it asks you for something, just hit enter. (Basically, it loads all the default configs). Once loaded, on the Gparted main screen, right click on your current xp partition, select Resize. Use the little slider to “shrink” your xp partition. I would keep atleast 4 GB to XP, just in case. After you are finished, click Apply Changes. For me, it took about 15 minutes, but for you it may take longer. Go ahead and make yourself a sandwich (Yum!)
6. Put your Ubuntu Live CD in.
Get your live CD and stick in your computer and boot. When the desktop loads, double click on install. When you hit the partition manager, look for a selection of “unallocated space” or “largest contiguous free space”, from there its a just a regular Ubuntu install. 30 minutes and you’ll be well on your way.
Enjoy
September 3, 2008 at 3:37 pm
You don’t have to download the GParted CD. Ubuntu’s own CD can resize the XP partition.
Also, I don’t know if this applies to all distros, but if you’re using a Ubuntu CD as your example anyway, Ubuntu has another installer called Wubi that sets up Ubuntu as a dual-boot from within Windows. There’s no need to defragment, repartition your drive, or mess with the boot loader.
September 3, 2008 at 11:43 pm
Actually, the Ubuntu CD Manager is rediculously slow, or atleast for my case. And Wubi runs ubuntu more out of windows using an ntfs drive which isn’t as fast as a seperate partition.