I have recently installed XP on my Aspire One. I followed the tutorial below which worked perfectly. The only thing I had a problem with was creating the bootable Flash Drive using Vista, but I had no issues when I tried again using my XP machine. The The flash drive size has to be at least 1 GB and the whole process should not take you more than an hour.
This tutorial uses an Acer Aspire One as an example but this method is fine to use for any other computer. I will also say that I am not too sure about using this method for different operating systems, so look elsewhere for installing Vista or anything else.