https://www.virtualbox.org/
https://my.vmware.com/web/vmware/free#desktop_end_user_computing/vmware_player/6_0
http://www.vmware.com/products/player/
Once the virtaul box is downloaded and installed, open it. To create a new virtual machine click on New.
Once you click on Create the virtual machine will be created. Press the start to power on the machine and insert a CD with Windows XP into the physical machine to start installing.
To change / modify the virtual machine settings you can always use "Settings" tab.
