"Installation of Proxmox is almost a "forehead"*
install requiring only that you accept the EULA, enter a root
password, an administrative email address and networking
information. The current Proxmox VE version, as of this writing is
1.2 (released May 12, 2009). The ISO image is just over 300MB.
Download it from PVE Downloads, burn the ISO image to a CD-R disc,
boot from the CD/DVD drive and follow the on-screen instructions.
This installation will overwrite your system's disk and is meant
for installation onto dedicated server hardware.
"Your hardware needs to be server quality with plenty of RAM,
disk and CPUs with virtualization extensions. You should use a
quad-core system if you're going to have more than a handful of VMs
running simultaneously."