The processor shouldn't make any real difference as to how you go about installing Ubuntu. Go to their website, download the latest image (10.04 LTS), either 32-bit or 64-bit, depending on your preference. Burn this image to a CD, and reboot your computer. Make sure the BIOS boot-order has your CD/DVD drive before you HDD. It's a very straight forward installation, and there's not a whole lot that can go wrong.
Sorry if I misunderstood your question, but that's what I took from it. Good luck