Just a few quick notes on how I got a CentOS v4.4 Xen dom0 to boot inside a VMWare Server VM…

yum install bridge-utils SDL

rpm -ivh xen-3.0.4.1-1.i386.rpm kernel-xen-2.6.16.33-3.0.4.1.i386.rpm

vi /etc/yum.conf
Add:
exclude=xen xen-kernel xen-devel kernel

mv /lib/tls /lib/tls.disabled

mkinitrd -f -v --preload=scsi_mod --preload=sd_mod --preload=mptbase --preload=mptscsih --preload=mptfc --preload=mptspi /boot/initrd-2.6.16.33-xen_3.0.4.1.img 2.6.16.33-xen_3.0.4.1

vi /boot/grub/grub.conf
Add:
  title Xen v3.0
  root (hd0,0)
  kernel /xen-3.0.gz noreboot dom0_mem=128000
  module /vmlinuz-2.6-xen root=/dev/VolGroup00/root
  module /initrd-2.6-xen.img

Reboot!