Partition
If you have read my Dual boot Ubuntu onto XP guide. This one will be similiar.. To get started boot up in Windows Vista and go into the Disk Management (right-click My Computer, go to manage, then Disk Management). Again, right-click on the main Vista partition and hit Shrink Volume.
The Shrink tool tells how much space can be freed up. In the menu type how much space to leave open. Try and give each OS atleast 10 GB of space to work with. Hit shrink and the tool will reduce the volume of Vista partition.
Installing Ubuntu
The first thing you should do before fully installing Ubuntu is deciding if you like it or not. You can do this by obtaining a copy of the Live CD or by downloading the ISO. You can do this by going to Ubuntu's website. If your internet speed is really slow and you do not want to bother with the time you can purchase the Live CD and it will be shipped to your house in 2 , to 4 business days. Remember you are just paying for the shipping. Or you can get a free Live CD by mail, but the downside is that it will take 10 to 20 business days to ship.
Now if you are going to download the Live CD from the website continue reading (If not skip this section). You are now at the download screen where it is asking you what version of Ubuntu do you want. You should check 7.10 under the desktop edition. After that is done, under what you just chose it should be asking you, "What type of computer do you have?" I run on an AMD 64 bit processor but for some reason it doesn't recognize the install disk correctly. So it is highly recommended you choose the first option, Standard personal computer. After this select the closest location near you under the drop down menu below the previous option. Then click start download. You will be redirected to a page that starts your download and asks you where to save it, just save it to desktop. Now go relax and wait for your download.
Supposing you have downloaded the ISO file of the Live CD and you are ready to host it. Go download Infra Recorder if you do not have a program that burns ISO files. If you are using Infra Recorder, insert your blank CD into your drive and if it auto loads select cancel, next open up Infra Recorder and select Actions > Burn Image, from here select your ISO file and hit open and it should begin to burn. After your image is complete you are ready to do a live boot of Ubuntu Gusty Gibbon.
Whether method you used to get a Live CD you should be ready to boot up in Ubuntu now. Insert your Live CD into your disk drive and restart your PC. When it gets to the screen where it displays your disk drives and memory amount you can either start mashing F9 or if you have timing just hit it once when you need to, to get to the boot menu. From here select boot from disk and a screen with multiple options of Ubuntu should pop up with the first option being "Start or Install Ubuntu", Select it and let Ubuntu load. The first time it loads off the CD it may take three or four minutes so be patient.
After the Live CD is done loading mess around with the Live session and see if you like it. After you decide that you want to install it (it is recommended that you back your window's portion of the guide) click the install icon on the desktop.
A welcome screen will come up and ask you what language you would wish to use. Then after that it will ask you what timezone you live in. Just select one that is relatively close to where you live. After this choose your appropriate keyboard layout.
Ubuntu will then load the disk partitioner to determine where it's going to be installed. Choose ,Manual - use the largest continuous free space. This will automatically select the unpartitioned space we created earlier using the Shrink tool. Click Forward. If you feel brave you can can edit the portions manually. After you have selected all of your needed information, Ubuntu has enough knowledge to install itself. Now go relax a second time if you have downloaded the CD, if not it will be your first!
After Ubuntu is done installing itself your computer will automatically reboot and will come up with the GRUB system select screen. Your very first option would be what you want to boot up in if you want Ubuntu, but if you want windows choose either the fourth or fifth option. After 10 seconds of no responding it will automatically boot up in Ubuntu. If you were like me and accidentally installed Ubuntu on your second HDD, you may have to reboot up into Vista for Ubuntu to recognize all of the hard drives and their space.
Now go out and enjoy your new operating system!